Two elderly brothers are found dead in their home, with no apparent injuries. A post mortem discovers suspicious puncture marks and a possible racist connection.

A third death helps Sam realise that the motive behind the murders of the Davies brothers was not racial - but revenge.

Sam is called in to identify the naked body of a woman uncovered on a ski slope in Norway.

DCI Norton dismisses Sam's idea that a serial killer is at work - until a third body is found at one of the victim's family homes.

A school director's wife commits suicide, but Sam suspects murder. During the investigation, she receives shocking news about her own health.