When a decomposed body is found hidden in the wall of an old factory building, Sam Ryan concludes he was murdered. He is eventually identified by his ex-girlfriend Selina Thomson as Marcus Saul, who had simply disappeared one day some seven years earlier. There has also been a break-in on campus and drugs have been stolen. The Dean asks Leo Dalton to speak to some of the students on the issue, but he's not quite sure what he can do.

With the death of a student from a drug overdose, the university must face the wrath of the girl's father, a major benefactor. The autopsy reveals that not only had she taken drugs but also that she had sexual relations with three different men in the previous 48 hours. Although the police have a suspect in the murder of Marcus Saul, new information suggests that the identity of the killer may lie in a completely different direction.

When teacher Lucy Chatham is abducted Nikki and Jack help police officers Andy Steemson and Karen Wretzy investigate the circumstances of her disappearance whilst Thomas assists abrasive DS Maureen Steele when ex-addict Tina Lunt is murdered. Doctor's daughter Jessica Timpson saw a car outside her house near the spot where Lucy was taken and her parents Nick and Ellie fear it may belong to Ellie's brother Alec Porter. Tina's death points to criminal boyfriend Wesley Beale whilst Lucy's sister's boyfriend Jasper Lampton is the key suspect when Lucy, his secret lover, is found dead. Forensic evidence suggests that both women were killed by the same man. Then Beale is murdered.

Ex-drug user Jasper is hauled in by Steemson for killing Beale, who had been his supplier but released again whilst Ellie confides her fear to Nick that Jessica is covering for Alec, whom he believes to be the murderer. Then Clarissa finds a link between Alec and a twenty year old crime in Brighton for which he was acquitted. As a result he goes on the run and Ellie finds herself in danger from an unexpected source before the multiple killer is caught.