Several years have passed since the warlock incident. Creed McIlveen and Justine are married, and have three children: Ricky, Cynthia and Eve. Creed now works for the Agency, a semi-official, black-ops crimefighting organisation. However, he’s having troubles at home; Ricky has been expelled from three schools, not because of anything he’s done, but because other people tend to get uneasy in his presence and trouble seems to follow him around. This is causing tension between Creed and Justine, and Creed is tempted to start an affair with his new co-worker Amy Cowan, who seems to reciprocate his attentions. Creed and Justine are trying to get Ricky into Scopes High School, an environment for troubled teenagers, but Alan Pangbourne, the principal, disapproves of the Agency and suspects that the McIlveens are keeping secrets from him. Creed “accidentally” meets Amy Cowan at the school, and Justine learns about it; nothing happened between them, although Creed was tempted, but Justine snaps nevertheless and admits to Ricky, in a fit of rage, that Creed is not his real father.

When Creed learns what Justine has done, he’s furious, and storms off to the Agency, where Amy is waiting, apparently working late. They begin to make love on Amy’s desk, but are interrupted by an intruder alarm. Creed investigates to find that the alarm was triggered by Buddy Stanmer, an arrogant young man who saw Amy and Creed together and has seized the opportunity to blackmail Creed and advance his own career in the Agency. However, he discovers that there is a real intruder in the building, who nearly went unnoticed due to the foolish false alarm. Creed is forced to shoot the young intruder to save Amy’s life, but then learns that the intruder has left a message on the supposedly unhackable computers -- a message from the Doctor, calling for Creed to come to England at once. Creed sets off immediately, and although he calls to tell Justine, she arrive too late, and he must leave without saying a proper goodbye to his family.

Benny and Roz are returning from a mission to Budapest when their plane runs into severe turbulence and nearly falls from the sky; however, their own calm attitude and relaxed body language keep anybody in the cabin from panicking, and the plane’s engines start up again. Flight attendant Jessica Morrell is relieved, as she has a lot to live for now; her lover Roy has just proposed to her. However, when he doesn’t show up at the airport, she assumes he’s reconsidered and storms off back home in a rage. Meanwhile, Benny and Roz are separated at customs when Roz is press-ganged into service by the psychic Mrs Woodcott, who takes one look at her and concludes that she has the skills required in this time of emergency. Dogs all across London have been going mad and attacking their owners, and although the government has been trying to keep the matter quiet, it’s getting steadily worse.

Pangbourne can find no records indicating why Ricky has been expelled from so many schools, and suspects that the Agency is responsible for “protecting” Creed’s son; however, Justine insists that the other principals and teachers have nothing but vague concerns which none of them were willing to put on the record. Pangbourne agrees to accept Ricky into Scopes, but he’s unable to tell Justine that he’s already been forced to take two undercover Agency members onto his staff. The new history teacher, Mr Retour, and the school’s “guidance counsellor” -- Amy Cowan -- begin to place Ricky in a series of stressful situations in order to guide his behaviour. Retour plants a note on Ricky’s lunch tray, claiming to know who his real father is, and as Ricky tries to recover from the shock Amy calls him on the P.A. system, making him the centre of attention while he’s incapable of hiding himself. The school bully, Christian “Wolf” Leemark, sees the beautiful Amy comforting the terrified and confused Ricky, and, jealous, vows to take Ricky down.

Roz and her new associate Redmond answer an emergency call from Jessica’s house; Roy didn’t show up because their pet terrier Scooter tore his throat out in the kitchen, and now Jessica is trapped in the house’s bedroom. Mrs Woodcott shows up to help them rescue Jessica, but they fail; stunned and disoriented by the trauma of Roy’s death, Jessica returns to the house to fetch a photograph of him and is brought down by an entire pack of wild dogs. Roz, Redmond and Mrs Woodcott flee, but as they go, Roz catches a glimpse of an elderly, emaciated white dog who seems to be directing the pack’s attack. Meanwhile, in the house on Allen Road, the Doctor and Benny notice that Jack, a man whom the Doctor has been keeping in a life-support capsule, is starting to stir to life as the howls of dogs echo about the countryside.

Retour lures Wolf Leemark’s father Francis to the school, and deliberately confronts Pangbourne about his work with the Agency, causing the principal to become irritated and unsettled before his meeting with Leemark. Leemark is a violent, fundamentalist bigot who opposes the inclusion of a Buddhist monk on the teaching staff, and when Pangbourne doesn’t show him the respect Leemark feels he deserves, Leemark snaps and strikes Pangbourne repeatedly in the head with his own ashtray. He then tries to gun down the young monk, but Ricky sees him and shouts out a warning -- and everybody in earshot reacts instinctively to the authority in Ricky’s voice. Even Leemark is distracted, enabling the Buddhist monk to overpower and disarm him. The Buddhist is then forced to go to Justine and admit the truth; he is Chris Cwej, and although the Doctor sent him in undercover to keep an eye on things, it appears that events are moving more quickly than the Doctor had feared. Due to her past experiences, her children are psychically gifted, and it appears that someone at the Agency is trying to turn Ricky into a weapon.

Upon arriving in England, Creed is also spotted and press-ganged into action by Mrs Woodcott. He thus accompanies Roz and Redmond back to Jessica’s estate, at the request of a civil servant named Norman Peverell who is skeptical of Roz’s claim to have seen the legendary White King, the elderly dog who is rumoured to lead the feral packs. When they arrive at the estate, however, the White King and his pack are waiting for them. Jessica is also there, kept as a prisoner by the pack in order to lure the others back. The dogs send her towards the tank, apparently in an attempt to prevent the weapons from firing on them, and Creed wastes valuable time trying to reprogramme the guns to target only dog-sized animals before discovering that this is already the software’s default setting. He then emerges from the tank to rescue Jessica, only to be attacked by a dog standing on top of another dog in order to confuse the weapons’ software. At the last moment, Jessica snaps out of her state of shock and kills the dogs, saving Creed’s life.

Roz and her associates are trapped in Jessica’s house as the pack circles, preparing to attack again, but at the last moment, the Doctor and Benny arrive with Jack’s body and a sample of warlock. When Jack was overdosed with warlock in an experimental fiasco, his mind left his body and entered the body of the dog now known as the White King. Trapped in a dog’s body, Jack learned how to direct the packs by body language and non-verbal communication; he has become the alpha male, the pack leader, and all this time he’s just been trying to communicate, to ask for help. The Doctor has now answered his call, and using the leftover warlock, he transfers Jack’s mind back into his body. The White King dies, and the feral pack disperses. But when Jack regains the use of his voice, he warns the Doctor that there’s another, greater danger out there; when Jack first tried to use his new abilities to ask for help, the man he tried to communicate with was Justine’s ex-husband, Vincent Wheaton. Vincent has become obsessed with revenge against Creed and Justine, and he’s learned much about the phenomenon of the alpha male from observing Jack’s behaviour with the dog packs. Vincent now knows that his son Ricky is a psychically-enhanced alpha male, who is capable of guiding the behaviour of crowds and perhaps entire societies -- and he has now reintroduced himself into Ricky’s life, under the name of Retour...

Vincent is working with the Agency, who have been keeping Creed in the dark about their true intentions for his family. It was Vincent who sent Creed the false message from the Doctor, in order to get him out of the way while Vincent guided Ricky into understanding his powers. With Ricky by his side, Vincent intends to rule the world; but first he will have his revenge on Creed and Justine. He sends Buddy Stanmer to kidnap Eve, but Roz arrives in time to save her, shooting Stanmer dead when he tries to pull a gun on her. Amy is sent to collect Creed, but he has already figured out that she’s working for Vincent; however, she claims that she fell in love with him while keeping him under surveillance, and they make love in her car.

Vincent, still acting as “Mr Retour,” tells Ricky that Pangbourne has died of his injuries, and claims that Pangbourne wanted Ricky to be the one to tell the school. When Ricky stands up in front of everybody with this devastating news he becomes the centre of attention, and he realises that he’ll never be able to shake off the other students’ unconscious worship; although their interaction remains unspoken, even Wolf now regards Ricky as the true power within the school. Terrified, Ricky flees from the school and tries to catch a train out of town, but he finds the other passengers reacting uncomfortably to his presence, and forces himself to calm down. The other passengers calm down as well, and Ricky, relieved, falls asleep... only to awaken hours later to find that everyone in the train, the station, and the surrounding streets has fallen asleep as well. One of Vincent’s goons arrives, holding Cynthia hostage; as Cynthia and Ricky are blood relatives the effect doesn’t work on her, and as long as the thug stays close to her he too remains awake. However, Jack arrives to rescue Ricky, and when the thug tries to set his dog on Jack, Jack easily turns the dog on the thug instead.

The Doctor arrives at Justine’s, only to find that Vincent has beaten him there, knocked Chris out and taken Justine hostage. Vincent accuses the Doctor of using him and then abandoning him, and reveals that when Justine betrayed him he lost the use of his powers. Amy arrives with Creed in tow, but as Vincent prepares to kill Creed and Justine, the Doctor begins to provoke him, claiming that he’s demonstrating his own weakness and insecurity. Vincent may believe that Ricky’s gifts are the legacy of Vincent’s own psychic powers, but the Doctor points out that Creed and Justine made love while Justine was pregnant and Creed had taken warlock. Under the influence of warlock, Creed once used his body language to destroy a gangster by demonstrating his weakness before his men; perhaps Creed is really Ricky’s father in every way that matters. As Vincent loses his temper and his self-control, the Doctor becomes the dominant alpha male in the group, and at the last moment, Amy shoots Vincent to save Justine’s life. Ricky now has to learn how to control his abilities, and the Doctor, Chris and Jack promise to help him. But Creed and Justine’s marriage is now over.