When the body of 21 year-old medical student Amy Penn is found by children in a park, the Taggart team prepare themselves for a difficult investigation. Heavy rain has destroyed any evidence of her killer, but strangely her body has been sculpted in death into a childlike pose with her thumb in her mouth. Initial enquiries uncover few leads. Amy was a hard-working, friendly girl, with no apparent enemies. Ross, however, fails to be convinced by her friend Donny Whyte. The discovery of another body on a ferry slipway puts a different perspective on the case. Neil Jones was a recovering alcoholic, found nursing a half-empty bottle. At a first glance his death seems accidental, but both bodies share almost identical neck wounds. Burke has to face the grim prospect of hunting for a serial killer. The connection between the victims proves strangely elusive until an unexpected twist leads the team to a therapy centre in the West End. Eager to crack the case, Jackie Reid volunteers to go undercover as a patient and against his better judgement Burke agrees. However Jackie hadnt banked on being forced to revisit painful memories from her own past. With the body count rising, the race is on to find the killer. But is Jackie in too deep?