Episode list

Autistic DS Stone's criticism of police handling in a recent case leads to his being demoted to a secondment to Missing Persons with motherly divorcee Ruth Hattersley. When 16-year old Taylor Davis goes missing, though she is a known runaway, Stone is convinced that she is in danger and discovers that she had joined a website for suicidal teenagers, two of whom had recently died in suspicious circumstances. Stone visits security guard John Meadows, who found the body of one of the boys, Kieran, but Stone is convinced Kieran was murdered. Aaron Scobie, who sold Taylor drugs, is arrested but denies knowledge of her disappearance and refers Stone to a girl Taylor met through the site called Leanne. Exasperated by Stone's attitude Ruth links up with Leanne by pretending to be a young girl. She goes to meet her at a deserted mall, where she is attacked.

Stone and Inspector Prior discover Ruth, who has been knocked out by 'Leanne' who is a man and Stone deduces that he lures teenagers to their deaths and make them appear to be suicides. Stone notes that sites where corpses were found and Ruth attacked are owned by a property company and visits their housing project, finding runaway Chloe Amos. She says that she was squatting in the building but was attacked by a man she disturbed and who escaped in a car, which Stone partially identifies. He is carpeted for his rude, unorthodox manner but traces the car to the company's security firm and John Meadows, who he is convinced is the murderer. Meadows is arrested but 'Leanne' posts another message, making Stone and Ruth realize that Meadows has an accomplice, who must be found in order to save Taylor.

Stone persuades Ruth to join him in investigating the disappearance of solicitor Steve Eli, tracing his last journey to a spot where two other men were slain. From this Stone deduces that taxi driver Leonard Vance, who killed both victims, also murdered Eli and he and Ruth interview Vance in a secure hospital in the company of his psychiatrist Dr Ellesmere and Alex Wernley, who wrote a book on Vance and other killers. Vance admits to killing Eli but claims not to remember where he hid the body and when Stone takes him to a likely burial place he collapses and is rushed to hospital. Stone now believes Vance to be innocent but when he gets to the hospital Ruth tells him that the man is dead.

Vance dies of a heart attack but Stone is convinced he is innocent of all the murders. He discovers that Eli was bipolar and was an out-patient at the Mayside psychiatric clinic, as were the other victims and Vance and that it was near to the murder scenes. Dr Ellesmere confesses that Wernley was her lover and she broke the rules by letting him speak to Vance regarding his book. Wernley told Vance about the other murders, leading him to believe that he was the culprit and to confess. When Stone finds that Ellesemere once worked at the Mayside she becomes a prime suspect but she is another victim, kidnapped by the real killer, who hates the mentally ill. The case is closed but then Stone is told that his carer, Adele, has gone missing.