George became a werewolf while on holiday in Scotland. He was about to go out for a walk when an American tourist, not knowing his way around, invited himself along after George reluctantly let him. They both got lost as night fell and were attacked by a werewolf–later revealed to be a man named Lee Tully, who later comes looking for him in search of companionship–who killed the tourist and scratched George, who survived when the rescue services found him.^[4] After becoming a werewolf, George left his family, his job and his fiancée, afraid of hurting them. He works alongside Mitchell as a porter in the local hospital, unable to hold down a more permanent job due to his monthly transformations, which are extremely painful.

George resents being a werewolf to the extent that he is essentially in denial about his condition, often referring to it as "that thing that happens to me once a month". For the whole of Series 1, he attempts to view his wolf side as an entirely different entity; when referring to his wolf self, he never uses "I" or "me", only an impersonal "it". His denial ends after the last episode of the first season, when he takes responsibility for his actions as a wolf after accidentally scratching Nina during a transformation whilst trying to protect her from the vampire Herrick.

George attempts to find new ways of coping with his "condition" in Series Two while trying to take action to lead a normal life. This includes such measures as caging himself and taking tranquilisers before transforming, but this apparently only makes the wolf angrier, resulting in uncontrollable swearing and a more brutal mentality in his human form, as though the wolf was trying to "get out" in revenge for being "chained". Matters become even worse when he accompanies Sam Danson, his new girlfriend, to her daughter Molly's Parents' Evening, only to nearly transform at the school because he is unaware that the clocks had gone back; although he manages to maintain control of himself long enough to get back to the flat and be locked in his cage by Annie. Molly's subsequent terror after seeing him mid-transformation prompts George to look into a cure for his condition once again, only to change his mind once again when Annie reminds him that he will be unable to see her as a human. He reunites with Nina, and they leave the chamber after finding a message from Tully written at the bottom of one of the walls: "George, all the werewolves die". He and Nina watch Annie being forced through the door and they, and Mitchell, later move to Wales because they are unable to stay in the house after losing Annie.

Having relocated to Barry Island, George and Nina start work at a new hospital, using the basement room of their new house for one of them to remain during the full moon. However, despite George's belief that he or Nina would kill the other if they transformed next to each other, the two of them apparently have sex while in wolf form. When Nina discovers the permanently teenage vampire Adam as his elderly father was admitted to the hospital shortly before his death, she and George briefly contemplate taking over responsibility for Adam after his parents' deaths–George speculating that they pretend that Adam was his brother until he and Nina were old enough for them to introduce him as their son–but Adam departs to make his own way, wanting to explore his own independence without being a burden on them like he was on his parents. As a result of their sexual intercourse while in wolf form, George and Nina are now expecting a baby. Following Herrick's resurrection, despite his knowledge of what Herrick was in the past, George refuses to allow Mitchell to stake Herrick as he wants to be the kind of father who can legitimately teach his child about redemption and forgiveness, feeling that the now amnesic Herrick deserves the same chance as they had given Mitchell.

When Annie finds a death notice for George's father in the paper, George attends the funeral and encounters what he believes is his father's ghost, only to subsequently learn that his father has actually faked his death after a homeless man burnt to death in his shed after his wife had an affair with George's old P.E. teacher. George and Nina are able to convince him to assert himself in his relationship with his wife, the two resuming their relationship with a trip to Cornwall (although they apparently believe that George has HIV rather than that he is a werewolf).

With the discovery that Mitchell was responsible for the Box Tunnel Twenty murders, he returns to the house to ask George to kill him, wanting to ensure that he could not kill anyone else and that George would be freed from the "taint" of helping him escape the consequences of his past sins. Understandably, George is reluctant to kill his best mate but when vampire Edgar Wyndham states out his intent to use Mitchell as an "attack dog", George carries out Mitchell's request and kills him (telling Mitchell that he is "doing this because he loves him"), and then kills Wyndham, in effect declaring war on the vampires.

The first episode of Series Four, "The Eve of the War", reveals that Nina had subsequently given birth to a daughter. However, it is also revealed that George's killing of Mitchell and Wyndham has resulted in a revenge attack from the local vampire coven (led by Griffin) who had ambushed Nina on her first trip outdoors after the birth and beat her to death in an alleyway. At the start of Series Four, a traumatised and grieving George has developed a siege mentality, shutting himself with his as-yet-unnamed baby in a single room in Honolulu Heights and taking up a position of constant vigilance against vampire attacks.

George is lured out of the house by an apparent opportunity to kill Griffin, which turns out to be a trick enabling the vampires to kidnap his baby with the intention of offering her as a gift to the Old Ones. George subsequently gives himself up to Griffin as an alternative trophy, in order to preserve her life. In the lair, he forces an off-schedule and partial werewolf transformation by tricking his body into believing that it is the full moon. Although this enables him to kill Griffin, destroy the coven and save his daughter, it also results in his death from kidney and heart failure following the botched transformation, as his body was undergoing the transformation into a werewolf without activating the accelerated healing that would allow him to cope with the organ damage. His last acts as he dies are to command Tom to take his place at Honolulu Heights with Annie and to give his daughter a name: Eve.

Born in 1893 and Irish by birth, Mitchell fought as a young soldier in World War I, when he was originally recruited as a vampire by William Herrick. He encountered Herrick after a battle, stumbled upon him and several other vampires who were picking through piles of bodies for anyone living to feed on. Mitchell agreed to feed Herrick and become a vampire in exchange for Herrick leaving the rest of his men alone. He rejoined his regiment, hoping that no one had realised that he has changed, but became so hungry that he stole poison from the medical supplies, killed one of his friends, and drained his blood before deserting the army and running away. At some later point, he rejoined Herrick and the vampire community, accepting his new vampire nature.

In his early years as a vampire (and before his conscience was reawakened), Mitchell was quite a hero within the vampire community, who still circulate stories of his exploits amongst themselves. These seem to be a cause of great guilt for Mitchell who has asked Herrick to stop the retelling of the stories as he would prefer to be forgotten.^[6] At several points, he has faced a conflict of emotions as he debated whether to "convert" people dying around him to prevent their deaths. In the 1960s, Herrick gave Mitchell the opportunity to kill a young girl that they had lured into their car. Mitchell showed guilt and anger at the easiness of the kill and let her go. He told Herrick that she had escaped, prompting the suspicious Herrick to say that he would keep a closer eye on Mitchell.^[7] Mitchell has attempted several times to abstain from drinking blood (one attempt was a New Year resolution for 2000, with the aid of a fellow vampire called Carl). At this time, Mitchell showed an extreme addiction to blood, as well as heightened aggression, lack of control and extreme panic due to blood withdrawal.^[8]

Mitchell's reluctant rescue of the werewolf George from a squad of fellow vampires, and the subsequent development of their friendship, further awakens his conscience, and he eventually opts to drift away from the vampire group in Bristol and to join George in living quietly. After "converting" Lauren into a vampire (as covered in both the pilot episode and Series One Episode 1), Mitchell, infuriated at himself, decides to fully give up the blood and to attempt "being human" once more. He continues to take care of George, particularly around the full moon when George transforms.

In episode 3 of Series 2, Mitchell has become the new "king" of the vampire group in Bristol, hiding evidence of their feedings, recreating their human front and intending to wean them off blood, although his activities are hampered by such problems as Ivan–his oldest apparent "recruit"–being unable to completely forsake blood after so long, forcing him to allow Ivan to feed in secret while maintaining his public front. After the deaths of his vampire group by an explosion at the funeral parlour, subsequently receiving confirmation that they have been betrayed by the coroner despite a deal he had made, Mitchell realises that he has wasted his time trying to hide his blood lust and goes on a frenzy with Ivan's widow Daisy. Paying a last visit to George and Annie, he briefly seems to return to normal when warning George to stay away from cities in future before returning to his more arrogant, blood-crazed ways. A confrontation with a priest while searching for Lucy reminds him that George saw him as a good man when he was injured by Herrick, and reveals Lucy's connection to the organisation that seeks to "cure" George and Annie. Finding the organisation's headquarters, Mitchell confronts Lucy, countering her claims that he and his kind are evil with both the theological argument that God made them just as he made mankind and by pointing out that she killed despite having a choice, but he nevertheless refuses to kill her or Kemp. He later shows evident grief when Lucy is killed by Kemp.

At the start of Series 3, Mitchell enters Purgatory to rescue Annie (following a terminally ill patient at the hospital where George and Nina now work through the Door after his demise). Although his mission is successful, he also learns that the time and date of his death have been confirmed, and he would be killed by a werewolf at some unspecified (but apparently not-too-distant) future date. While claiming to Annie that he has not believed a word of what he heard, Mitchell is in fact increasingly haunted by both the "prophecy" of his death and by the continued police hunt for the person responsible for the "Box Tunnel Twenty" massacre. He rejects an offer to depart Britain to live with the vampire "Old Ones", commenting during a talk with permanently teenage vampire Adam that his friends help him remain clean as their goodness inspires him by forcing him to think about the disappointment they would feel if he were to succumb to his thirst.

After a confrontation with vampire "fan" Graham, Mitchell tries to tell Annie the truth about the massacre, but Annie simply tells him that whatever he had to tell her does not matter, assuring him that all she wants is the man he is now and that what he had done in the past does not matter compared to what he has done for her and George. The two finally admit their love for each other and begin a romantic relationship. Although Annie tries to find ways for their relationship to become physical at first, Mitchell eventually admits that sex has always been about violence rather than love with him, and suggests that their "pure" relationship can be better than a sexual relationship.

Mitchell has a tense relationship with werewolf vampire-hunter McNair due to Mitchell's concerns regarding the "prophecy" of his death (despite having claimed to Annie that he does not believe in fate). He reaches a certain understanding with McNair once they work together to save George and Nina from a group of vampires, although McNair still feels that Mitchell's sins will catch up to him eventually. When Herrick returns to life, Mitchell initially attempts to stake him–particularly after Cara stakes herself before being able to tell Mitchell how she and Daisy have brought Herrick back. He is convinced by George to let Herrick live on the grounds that he deserves the same chances everyone had given Mitchell.

When Annie learns about Mitchell's role in the massacre, she tearfully convinces him to allow himself to be arrested. Mitchell goes along with it to prove his love for her, even as he tries to escape being processed due to the risks if his true nature is exposed. Although Herrick releases Mitchell–revealing in the process that his resurrection was aided by the fact that he was torn apart rather than just being staked–Mitchell finally stakes Herrick when he concludes that he has seen and done enough in his life.

On hearing the news that another man has been framed for the Box Tunnel Twenty massacre, Mitchell recognises that other vampires has set up that frame, and will call in a favour from him later. Sickened by his ultimate inability to escape his past, Mitchell decides that he wants to free his friends of the taint he has brought to their lives. He returns to Honolulu Heights to ask George to kill him–not realising that he is being followed by Wyndham, one of the Old Ones. George is initially reluctant to carry out Mitchell's wishes, but once Wyndham has spelled out his plans to use Mitchell as an "attack dog", George stakes Mitchell in order to save him from this final abuse. George's last words to Mitchell are, "I'm doing this because I love you," to which a grateful Mitchell responds, "I know," before he dies.

Nina and George go through tough times during the first episode in season 2, which concludes with Nina revealing her scratch marks to George and that she is now a werewolf as well, during an argument. In episode 2 Nina and George try to make things work, but Nina leaves George upon discovering that he helped a vampire who killed his own lover escape the country, subsequently being contacted by the mysterious Kemp and participating in research for a werewolf "cure" (Unaware that Kemp's experiment with a hyperbaric chamber would have killed her if it weren't for the intervention of Professor Lucy Jaggat). While George and Mitchell are willing to be around Lucy after her true agenda is exposed, Nina is furious that she was willing to lead them to their deaths and harboured an intense dislike for her. She moves to Wales with George and Mitchell after Annie goes through the door.

At the start of Series Three (and during her first transformation at their new home at Honolulu Heights), Nina and George apparently have sex while in wolf form, despite George's belief that one of them would kill the other if they transformed in close proximity to each other. After learning that she was pregnant as a result of her and George's intercourse while in wolf form, Nina admits that her mother abused her when she was a child, and was contemplating terminating the pregnancy both because she fears the consequences of two werewolves creating a child and because she is afraid of repeating her mother's treatment of her. Although they have not yet been able to determine what the baby will look like when born, or if it will "inherit" the werewolf "gene", Nina has apparently kept the baby despite the stress of her first pregnant transformation, although it is unclear how this will work as her condition progresses. When George and Nina arranged an ultrasound to examine their baby at the eight-week stage, the nurse carrying out the operation noted that Nina appeared to be sixteen weeks along. George speculated that this was just the result of werewolves gestating faster than humans, much like conventional wolves.

Despite her preoccupation with her pregnancy, Nina remains involved in other events at and around Honolulu Heights. She assists George in helping the permanently teenage vampire Adam, with the two briefly contemplating taking over responsibility for Adam after his parents' deaths from old age. Adam ultimately departs to make his own way, wanting to explore his own independence without being a burden on them like he was on his parents. Nina is also affected by the household's encounter with the zombie Sasha. Her decision to keep the baby is cemented by Sasha's declaration that her only regret was missing so many moments in life because she was more focused on the present than the future.

Matters come to a head when she and George recognise and kidnap a revived but amnesiac Herrick when he's brought into the hospital. She and Mitchell have a confrontation regarding Herrick's ultimate fate: when Herrick discovers Mitchell's "diary" of the Box Tunnel Murders, he shares this with Nina, who begins to turn against Mitchell and eventually betrays him to the police. Mitchell in turn begins to suspect that Nina is the werewolf "prophesied" to kill him.

Following Mitchell's arrest, Nina is stabbed by the now-restored Herrick as a revenge on George. While Herrick expresses a polite regret for his action (especially given that Nina was the only person in the house to show him kindness), he is hell-bent on making George suffer in the way that he did when George killed him. Fortunately, Annie is able to convince the manipulative ghost Lia to help her save Nina and the baby after convincing Lia that revenge couldn't solve anything.

In between the events of Series Three and Four, Nina gave birth to a baby girl. Shortly afterwards, she was killed in a revenge attack by the Barry vampire community. As with the birth of her daughter, Nina's death occurred off screen.

Although Thomas had lived his life believing that he was McNair's son, born a werewolf and that his mother had died during a vampire attack. However, Nina's subsequent examination of his blood revealed that he was actually the child of a random couple McNair had attacked during an early transformation in Cornwall. McNair had subsequently taken him in out of conscience as he realised that he had "infected" the boy with the werewolf "contagion'. Although he was briefly attracted to Nina, he pushed this aside after he learned the truth about the nature of the "wolf'. Initially angry at McNair for lying to him about his past, the two appeared to reconcile after McNair and Mitchell rescued him, George and Nina from a cage-fight, although he seems to be more interested in making his own way.^[9]

Following McNair's death at the hands of Herrick, Thomas is once again orphaned. Despite McNair's last wish being that Thomas does not carry on his adoptive father's feud against vampires, the grief-stricken Thomas pursues Herrick and Mitchell to avenge McNair's death, killing at least two vampires along the way, although he is prevented from taking full vengeance due to a Mexican stand-off involving a threat to George. Subsequently, Tom has lingered in Barry and been welcomed into the Honolulu Heights community, where he tries to learn to live like a human, love like a human and fight like a human.

At the start of Series Four, it's revealed that Tom has not entirely put his nomadic life and his vampire-killing mission behind him, but that loneliness is driving him to seek a permanent home at Honolulu Heights while he also works in a cafe. Following the death of George, Tom takes his place as Annie's best friend and helper, giving up his camper van to the renegade vampire Dewi who needs to escape from Barry. Although he does not entirely trust new housemate Hal, keeping stakes available even after arranging for Hal to get a job in the cafe where he works to help Hal pay for his share at Honolulu Heights, they have formed the beginning of a tentative friendship through their mutual distaste at the exploitation of women in the modern media. Tom has recently celebrated his twenty-first birthday, which — after some tension caused when murderous ghost Kirby convinced Tom that Hal and Annie were ignoring it when they were actually just unaware — Annie and Hal celebrated by preparing a cake for him. He recently had his first relationship with another werewolf named Allison, but forcibly ended it when he became concerned about the more violent tendencies she was beginning to develop due to her time with him, telling her to return to her parents so that she could have a normal life as a human for the days of the month when she wasn't a werewolf. Although the vampire Cutler attempted to manipulate Tom into putting himself into a position where he would attack innocent people in a club in werewolf form, Hal was able to evacuate the club before wolf-Tom could harm anyone. With Eve dead and Annie having crossed over after they destroyed the Old Ones, Tom has taken it upon himself to work with new ghost Alex to help Hal "detox" from his recent relapse into blood, commenting to Hal that he won't stake the vampire as Hal is "[his] best mate".

After Hal has finished 'detoxing', Tom and Hal take new jobs at the Barry Grand Hotel- Tom noting that he had always wanted to work in a hotel-, the two generally making a good impression on their new employers.

Hal's own actions anticipate and echo those of Mitchell in his recent attempts to refrain from blood-drinking. Since 1955, he has set up home in Southend with his two best friends, the werewolf Leo and the ghost Pearl (much as Mitchell set up home with George and Annie). Hal has kept his life to a rigid structure and kept away from all other people: he refers to his household and their house in Southend as the "cage" to which he submits to keep both himself and the outside world safe. By the start of Series Four, this arrangement has become threatened by Leo's passage into old age and ill-health (with the threat that he might not survive many more werewolf transformations). As the only member of the trio who can pose as a normal human, Leo is the one who owns their property and their source of livelihood (a barber's shop). Furthermore, his eventual death will result in Pearl's "fading" as she loses her physical home and "familiar" friends. Overhearing a "message" on a radio, Leo is inspired to travel to the house to visit Eve, but although she fails to cure him, he is nevertheless content to pass on with Pearl after admitting his love for her, with Hal deciding — albeit reluctantly, given the personality clashes - to remain in the house with Tom and Annie as his new "support group". Hal's character notes on the BBC 3 Being Human page state that "coming to Honolulu Heights is a huge disruption for Hal. And he doesn’t cope well with disruption. At first, Hal – the stand-offish, posh vampire – and Tom – the common, feral werewolf – find themselves at loggerheads, but once a mutual respect is gained, we see this odd couple become close."^[11]

Although their relationship is generally uncomfortable as Tom and Annie "force" him to start working in a cafe to support himself despite the disruption to his routine, Hal proves himself even after his status as an Old One is revealed when he stakes Fergus and various other vampires to help protect Eve. Although he and Tom have come to form a tentative friendship, after an injury sustained when Tom's blood left a significantly sized burn on his upper arm, Hal has become concerned that he is the "burned man" prophesied to be Eve's nemesis. Although he became the leader of the vampire conquest of the world in Eve's future, in the present created by Eve's future ghost interfering in the past Hal was redeemed and changed by his interaction with Tom and Annie, to the point where he not only rejected Cutler's attempts to lure him back onto the vampires' side, but actually helped to thwart Cutler's plan to demonise werewolves. Although Hal was intimidated at the presence of ancient vampire Mr Snow, who confidently informed Hal that he would join the other vampires regardless, Tom and Alex — a new ghost who had been killed by Cutler as part of his plan to lure Hal back into the fold- were able to save him from the destruction of the other Old Ones, the two subsequently resolving to help Hal detox from blood once again and break him from the cycle of slipping back into his old urges.

After spending a month in detox, Hal recovers enough to be released, swearing on Eve's memory that he will allow Tom and Alex to stake him if he relapses. He accidentally causes an accident when he scares a man named Ian Cram into running into a car after he sees Hal's fangs, but Hal's attempt to save his life by turning him into a vampire backfires when Cram escapes and kills his former co-workers before he is able to cope with his new thirst. Cram (now calling himself "Crumb") is taken prisoner, but Hal is haunted by an encounter with Dominic Rook — head of a supernatural observation organization — where Rook offered Hal a fresh supply of blood if Hal took control of the vampires. Hal and Tom are currently working in the Barry Grand Hotel, although Hal is unaware that one of the guests is the Devil's human host.

On holiday in Barry with her family (only one of whom has appeared onscreen so far), Alex encounters Hal at the cafe and becomes romantically involved with him. She initially (and unintentionally) bewilders and intimidates Hal, who cannot understand her attitude and initially shakes her off when she attempts to flirt with him: but Alex remains sufficiently interested to return to the cafe and leave her number for him.

Tom impulsively invites Alex to join him, Hal and Allison for a double date at a museum. During the date, Alex is led to believe that Hal's reticence is due to him having trouble adjusting after a prior relationship breakdown, and she assures Hal that she didn't expect anything long-term. Hal is in fact fighting off the desire to feed from her, and runs away. Tom and Allison convince him to go back, as he is simply running away from potential relationships. Hal begins to cautiously date Alex, but (under Cutler's influence) begins to drink blood again: the resulting, more licentious change in his personality repels Alex, who rejects him.

While trailing Hal, Cutler's henchmen note and pursue Alex: she is captured and subsequently killed, fatally drained of blood as part of Cutler's plot to both seduce and punish Hal. Although Alex dies, she returns as a ghost. She berates Hal for his unwitting role in her death, but still opts to help him to save Tom and the other victims of Cutler's broader plotting, and to subsequently fight against the Old Ones. She goes on to rescue Hal from the explosion which eventually destroys the other Old Ones. During this period, Alex's corpse is removed and hidden by a mysterious clean-up team led by Mr Rook.

At the end of Series 4, Alex has taken the departed Annie's place at Honolulu Heights, becoming the new ghost in the tripartite vampire/werewolf/ghost equation with Tom and Hal (echoing the previous Mitchell/George/Annie and Hal/Leo/Pearl relationships). She is shown helping Tom restrain Hal so that they can break him from the cycle that he has trapped himself in of resisting and succumbing to his urge for blood. While Kate Bracken's return as Alex was not stated by the BBC in press releases concerning Series 5, she stated in an interview that she would indeed be returning.^[12]

Although Alex initially assumed that her unfinished business was to recover her body and return it to her family, she is shocked to learn that her family had already buried her, leaving her confused at her continued existence on Earth. She continues to struggle with her ghostly heritage, occasionally trying and failing to eat despite failed past attempts.

Rook first appears approximately halfway through the final episode of Series 4 (The War Child) when he is briefly seen as the leader of a clean-up team which covertly enters Cutler's nightclub in Barry and removes Alex's mutilated corpse. It is clear that he has led many such operations before as he and his team confidently work within a forty-five second operational time limit. Rook appears again in the closing minutes of the episode when he is seen intimidating a woman who'd witnessed Tom's appearance in werewolf form at the Barry nightclub. Via intimated threats, he compels her to keep her silence and surrender her recorded evidence. He subsequently brings the latter to a staffed storage bunker concealed in woodland, in which vast amounts of such evidence (such as that remaining at the Kemp/Jaggatt facility from Series 2) is logged and concealed.

Rook and the Men in Grey play a more prominent role in Series 5, when they fall victim to government budget cuts which will close the department within three months. Distraught by the news, Rook is driven to increasingly desperate measures and moral compromise in order to save the Men in Grey and his own life's work. Having captured Hetty (the only other surviving vampire Old One), he learned of Hal's existence, and contacted him. Rook offered to aid Hal in his blood addiction by providing him with a controlled supply of blood, in exchange for Hal taking control of the vampires and steering them towards a workable situation living alongside human beings. Hal rejected the offer, but remained in contact with Rook, whose services he enlisted in containing the recently turned vampire Crumb.

While not a priority, Rook was also aware of the suspicious circumstances surrounding a series of suicides at the Barry Grand Hotel. Knowing that Hal and Tom are working at the hotel, he asked Hal to monitor the situation there, and report back to him. Manipulated by Captain Hatch, a resident of Barry Grand and the Devil incarnate, Rook attempted to stage a massacre at the hotel. However, this plan was averted when Tom and Hal were able to contain Bobby, the werewolf Rook had released. Simultaneously, Rook dispatched Hal to contain the released Crumb and his convert, Alan. This plan also failed when Crumb staked Alan and committed suicide.

Prior to the events of the series, Rook rescued and recruited Natasha, a child captured by vampires. He later tasked her with infiltrating the Barry Grand Hotel, and from there, Honolulu Heights. Natasha began a relationship with Tom, whilst providing her blood as a way of sating Hal's lust. Through this, she manipulated the two into a feud. When Natasha began to doubt Rook's leadership and cause, Hatch manipulated her into committing suicide in front of Hal.

Herrick appeared in a flashback in Series Two during a visit he and Mitchell made to London in 1969, during which he revealed that there is a similar system in London to the one which exists in Bristol, but he doesn't get along with the head vampire in London – the vampire's identity was never named – because he killed the vampire's mother under unrevealed circumstances. In the Series Two finale, Herrick was resurrected by Daisy and Cara after they slit their wrists over his grave. It was possible for them to resurrect Herrick because his head wasn’t cut off. He was just ripped apart and to kill a vampire properly their head needs to be cut off.^[18]

Herrick returned in the fifth episode of Series Three, apparently traumatised by what he experienced while dead, as he is seen in a hospital in a straitjacket, showing terror when Mitchell attacks him and confused when he realises that he cannot see his reflection in a mirror. Despite his apparent personality changes, such as his attempt to console George over his fears about becoming a father, his expressed disdain for Annie's goodness, coupled with him directing Nina to a scrapbook of Mitchell's past murders, suggests that some part of him remains underneath his amnesia. Mitchell has agreed to spare Herrick on George's request, but is also determined to discover the secret of Herrick's resurrection so that he can use it to escape his apparently prophesied demise. Mitchell's attempts to restore Herrick's memory met with failure; although Mitchell speculated that human blood would restore Herrick's memory, he is naturally reluctant to go that far himself, while Herrick displayed an apparent discomfort at the idea of drinking from police detective Nancy Reed when she came to question Mitchell based on an anonymous tip about the Box Tunnel 20, although he was clearly tempted to do so despite his amnesia. Herrick was partially restored to himself after killing the werewolf McNair (who attempted to kill Herrick because McNair had become infected with lycanthropy when Herrick put him in a cage to fight a werewolf) and made a full return to awareness and memory when he drank Nancy after she led the police team to arrest Mitchell. He subsequently slaughtered the rest of the police team in the house, and then captured Nina on her return alone to the house. Despite expressing "a dilemma" over whether to kill Nina in order to pay George back for killing him, or to let her live due to her kindness to him, Herrick chose to stab her (commenting that if he didn't "people would think I've gone soft..."). He dies at the end of series 3 (The wolf-shaped bullet) by getting staked by Mitchell while he is distracted by a sunrise.

Hetty reappears in Series 4, when she travels to Britain with the other Old Ones. She is initially mentioned in one of the episode cold opens (set in 1855) in which Fergus states that Hal and Hetty know each other and that Hetty was one of the Old Ones who fears him. Hetty is subsequently seen in the group of Old Ones who appear in the penultimate episode of Series 4 and are killed by Annie's bomb: she escapes the building before the explosion. She later reappears in the opening episode of Series 5 ("The Trinity") as a captive of Dominic Rook and the Men in Grey. In this episode, she agrees to tell Rook everything she knows about Hal (now the only other surviving Old One) in exchange for being flown back secretly to Bolivia.

The ghost in question (initially credited as "The Woman") was the ruthless former leader of a London-based human resistance movement during the time of vampire dominion over the world. In the future, with the resistance gradually losing the battle, she had consulted stolen vampire lore and found out deeply troubling information about Eve's role as War Child. In an attempt to destroy the War Child, she had herself killed in order to pass into Purgatory as a ghost. Purgatory's coterminous existence with all times enabled her to access the past and mount a series of campaigns in order to destroy Eve in the present. She attempted several methods including autosuggestion via radio and television (in the manner of Purgatory's Gatekeepers, as seen in Series 2) and sending another ghost (Kirby) back to the living world as an assassin. The Woman's full identity and agenda — as well as the full nature of her knowledge regarding the War Child — was initially unrevealed, although she apparently knew a great deal about Eve's mother Nina and was therefore able to provide Kirby with enough private information for him to convince Annie that he had been sent by Nina to help them.

The Woman's true identity was revealed in "Puppy Love" and expanded upon in "Making History", when she revealed herself to Annie and addressed her as "Mum". She was the adult version of Eve, attempting to destroy herself in an attempt to destroy the future which she lived in, and which had been formed due to the vampire prophecies/parchments about her; the Old One Mr. Snow points out (episode 8) that their piece of the parchments state that Eve's death would prevent the Old One's plan to take over the world. Snow tells Annie he will help Annie protect Eve, and speculates that Eve would allow the vampires to win because humans would be so busy looking to Eve to save them that they wouldn't rally themselves against the vampires until it was too late. The adult Eve showed Annie what the future was like (a vampire tyranny in which all but the vampires were dead, dying or farmed for blood) and attempted to persuade Annie to avert the future by killing baby Eve herself. Annie's love for the infant Eve made her reluctant to do this, or to abandon her role as protector.

Annie eventually caused Eve's death in the final episode of Series 4 (The War Child) when her only remaining option was to trigger an explosion which destroyed the Old Ones and ended their plans for world conquest. This explosion also killed baby Eve, proving that the parchments were correct in predicting "that Eve's death is the key to humanity's survival" (stated by Milo in episode 8) by killing the scheming Old Ones (though two are seen escaping first) without actually killing the world's 'average' vampires. Eve's (and the Old Ones') death also concluded Annie's own "unfinished business" on Earth, finally allowing her to pass into the afterlife through her own Door. Arriving there, Annie found baby Eve and also met the adult Eve one last time before the latter dissipated and vanished. Before fading from existence, adult Eve thanked Annie and reassured her that the terrible future Eve had grown up into (and the person she'd been forced to become) had both now been erased. Annie then took baby Eve through a further door within the afterlife, with a strong implication that Eve's parents (and Mitchell) were on the other side of it.

Cutler was recruited as a vampire in 1950 by Hal (at the time cruel, committed to evil and posing as a crime boss). He was targeted as a replacement lawyer for the vampires following the death of their last one. Cutler was reluctant to kill humans in the beginning, although he began to cooperate once he began craving blood to the point of addiction. Some time after his turning, Hal demanded that Cutler kill his own wife in order to "shed his human life". Following Cutler's refusal Hal secretly trapped and drained her himself, tricking Cutler into drinking her blood unknowingly, before showing him her body as a lesson. The lesson must have worked as in the present Cutler has no problem manipulating or killing humans although he still feels guilt, confusion and anger at Hal for making him 'abandon his entire species'.

During the whole of Series 4, Cutler devised and put into action a vampire-protecting plot, intending to set up an anti-werewolf panic amongst humans which would encourage the latter to seek vampire assistance. He groomed an unwitting Tom as his main tool in this, first secretly filming him transforming and then winning his trust by helping him escape assault charges (Cutler persuaded police that the CCTV footage of the alleged assault showed that Tom wasn't actually fighting anyone — in fact, the vampire Tom fought was invisible to camera). When Golda, an agent of the Old Ones arrived in Barry, attempting to capture Tom and jeopardise Cutler's plans for him, Cutler first attempted to use Tom to eliminate Golda, and subsequently chose to stake her himself when the opportunity arose.

Cutler went on to post the video of George and Tom transforming up onto the Internet, winning the attention of various websurfers and newsgroup. He went on to stage a "grand reveal" in which a wolf-form Tom would be tricked into massacring humans on camera, resulting in footage which would go viral and incite an anti-werewolf movement. When Mr Snow and the Old Ones arrive Cutler attempted to present the results to them as a tribute but was astonished to discover that there was nothing relating to his plan on any news channel (Unknown to Cutler, an independent organisation involving Mr Rook had already gone to work on the cover-up). An infuriated Mr Snow verbally humiliated Cutler. Enraged, Cutler turns on the Old Ones and proceeds to carry out his own world domination plans, beginning with an attempt on baby Eve's life. By sheer willpower, Cutler forced his way into Honolulu Heights, although entering without an invitation caused pain and disfiguring burning all over his body. He was finally killed by Annie, who staked him via telekinesis before he could complete his goal.

As Allison and Tom train together, they begin to fall in love, prompting a double-date with Hal and Alex: this is interrupted when Cutler sets Allison and Tom up to confront and kill the vampire Kane. Their defeat of Kane leaves Allison aroused and she attempts to pull Tom into a full sexual relationship, but he is dismayed that he is turning her into a killer. Allison hunts Golda, but Tom dissuades her from killing: he persuades her that her parents still love her, and that there are ways of staying human even if she turns into a werewolf once a month. Allison still wants to stay with Tom and he finally has to reject her, ordering her to leave and claiming that he doesn't care about her (in order to convince her to return to her human life and escape the violence of his). Despite her departure, Allison's influence stays with Tom and inspires his decision to end his vampire-slaying activities.^[35]

Crumb was recruited out of desperation by Hal, who had unwittingly caused his death in a traffic accident. Hal recruited Crumb in order to save his life as best he could (although there's also a possibility, voiced openly by Crumb, that Hal also needed to create a potentially vicious enemy in order to assert himself as "good" in contrast). Hal originally kept Crumb prisoner in the basement at Honolulu Heights, although he kept this secret from Tom and Alex: when they discovered Crumb's presence, Alex released him.

During Crumb's life as a human, he was persistently bullied, ignored or passed over, resulting in a growing sense of aggrievement. He was also single, with his only known relatives or intimates being his sister and niece (whose photograph he kept in his wallet). At the time of his recruitment, Crumb was on the verge of being bullied out of his low-level office job, and he took this particular resentment with him when defining himself as a vampire. When faced with his final dismissal, he opted for a generalised vengeance on humanity, locked himself in the office with his former colleagues, then killed and fed on his replacement. He has since been taken into the custody of Dominic Rook and the Men in Grey, who also covered up the murder. Crumb's existence and murderous intent has also served to test and strengthen the bond between Hal, Tom and Alex, who have all agreed to share the responsibility for letting Crumb loose on the world.

Crumb's confused, destructive and predatory tendencies are currently being manipulated by Dominic Rook, who is using them to demonstrate to Alistair Frith that the Men in Grey are still needed to protect against supernatural threat. To this end, Rook stage-managed a meeting between Crumb and Crumb's sister and niece at the height of Crumb's blood craving. Crumb killed and fed on both women, and this was filmed by Rook for Frith's viewing, after which Crumb was apparently released by Rook, stating that his imprisonment by the Men in Grey was "sort of over now". While Crumb's human emotions are being rapidly eroded by his growing vampire nature, he refers to this in particular as "a sore point" and has exhibited flashes of remorse, horror and grief over his actions. Crumb has recently recruited a new vampire — Alan, one of the Men in Grey who chose to join him following a moral crisis.

Crumb and Alan were eventually confronted by Hal and Alex, Hal attempting to offer them another chance. Frustrated at his life and shaken at his possible future, Crumb eventually drank a glass of blood, which turned out to be Tom's blood, the werewolf blood causing Crumb to collapse.

Hatch is subsequently encountered in the present day, living semi-anonymously as a pensioner in the Barry Grand Hotel. At this point Hatch appears to be paraplegic and confined to a wheelchair. He displays some of his true nature in the form of negative human characteristics (bitterness, viciousness, outspoken racism and covert manipulative behaviour) and in his appearance (disheveled verging on decaying), as well as having a minor effect on his environment by causing freshly-picked flowers to decay just by passing by them. Towards the end of his debut episode, it's revealed that he is behind the spate of suicides at the Hotel when he whispers "a little secret" into the ear of the maid Sophie, who's subsequently driven to kill herself (and, before she does so, to write "He Is Risen" in letters of blood on the wall). Hatch has gone on to foment further trouble, conflict and suicide at the hotel, creating the spiritual pain and misery on which he feeds. He is using this to strengthen himself in order to regain his godhood, following which he plans to ravage the world.

When Hal and Tom take jobs at the hotel where he is currently staying, Hatch sees a prime opportunity to gain plenty of energy from a vampire/werewolf conflict and devotes himself to promoting discord between them. He feels threatened by the trinity relationship of Tom, Hal and Alex and is working on plans to isolate and "get rid of" Alex. He has demonstrated a working relationship with the Men With Sticks And Rope (whom he has referred to as "my boys"): this is sufficient to get them to attempt to seize Alex and drag her into the afterlife, Hatch using his powers to trap Alex in the house before Oliver, a child ghost, manages to defeat the Men With Sticks And Rope by closing the door and cutting them off from their life source. He later attempted to provoke another conflict by engineering a situation where Bobby, a socially awkward werewolf, would be unleashed upon the hotel after his transformation and Hal forced to fight him, but this plan failed when Tom contained Bobby himself.

It soon became clear that Oliver was literally haunted — by the ghost of Albert, who appeared in Honolulu Heights dripping with the water of his drowning. It was also revealed that Oliver was being used by the Gatekeepers (and, ultimately, Hatch) as part of a plot to seize Alex and drag her into the afterlife: a squad of Gatekeepers, given extra power by Hatch, came after the three ghosts with the intention of dragging them into Hell. This plot ultimately failed thanks to a mixture of his last-minute repentance and Alex's quick thinking. Both Oliver and Albert (who was only pursuing his brother in order to try to comfort him) passed on into the afterlife and closed their ghost door behind them, marooning the squad of Gatekeepers in the world of the living (where, cut off from their life force, they soon dissipated).

This situation is upset by the involvement of Alex, who discovers Mary’s true personality. Mary is delighted to have a new friend who she feels can understand and share her present-day interests (which include sexual voyeurism, mental eavesdropping and malicious manipulation of living people). Alex is alarmed at Mary’s unbalanced lack of restraint and perspective, believing that a similar fate might await her if she remains an earthbound ghost for too long. Setting herself the task of breaking the delusion which she thinks stops Mary from passing over, Alex engineers a confrontation in which both Hal and Mary learn the truth about each other. While both are horrified, Mary is enraged and later attempts to stake Hal by telekinesis, only barely fended off and persuaded against it by Tom and Alex. Breaking her friendship with Hal, but not yet presented with any more doors to the afterlife, Mary resolves to leave the stately home and go travelling instead, but not before warning Alex that her own efforts to keep Hal from killing are doomed to failure.

With help from Hal, a crestfallen Tom eventually realises that Larry is a fraud. Far from being a successful celebrity and speaker, Larry is destitute. Since becoming a werewolf, he has lost discipline and succumbed to various urges including infidelity and unreliability, which resulted in him losing his marriage, job and social position. Bitter and resentful, Larry refuses to take any personal responsibility for what has happened: instead he claims that his lycanthropy denied him any choices ("the wolf took it all") and that Tom’s attempts to better himself will always result in similar failure. Heartbroken and despaiting, Tom temporarily leaves Honolulu Heights to live rough, until he is persuaded to return by Hal and Alex, who emphasise their faith in his ability to cope with his condition.

Hal, meanwhile, has given Larry a final warning and ordered him to leave. Unwilling to depart from Honolulu Heights to return to living rough (and, perhaps, nursing a deathwish) Larry instead goads Hal into assuming full vampire state and attacking him. Hal strangles Larry to death with a telephone cord. Keeping this new murder secret from his housemates, Hal subsequently calls Dominic Rook to come and dispose of the body, therefore bringing Rook and DoDD directly back into the lives of himself, Tom and Alex.