The death of a tenant from a local hostel brings together the police and a civilian investigator, the investigation leads them into a dark, murky world where the vulnerable are manipulated and the guilty are being punished one by one. Each victim has a likely suspect but no one person has the means, motive and opportunity to be responsible for all the murders, who is the common link and can they find out before someone else dies? Sarah is an experienced service manager in social care, when she's called in to investigate the death of one of the residents at a hostel she becomes embroiled in a criminal investigation. Adam is a police officer in the jigsaw team but someone is killing off his caseload one by one, can he catch the killer before they strike again?