The hunt is on for Sandy's attacker, before a shocking confession causes tensions to boil over and some Islanders take justice into their own hands.
The race is on to catch Sandy's attacker before he can escape Shetland, while Lynda Morton finds herself in trouble, so she desperately calls Perez for help - offering a key name for his investigation in return. Blood from the recent break-in throws up a DNA match that leads to another murder suspect, and a shocking confession causes tensions to boil over, sowing the seeds of further violence.