As summer draws to a close in Shetland, indomitable sailor Cass Lynch is preparing to look after eccentric, outspoken Tamar, who is returning from hospital following a fall. Recuperation should involve a peaceful week in Tamar's isolated cottage but, on arriving at the house, Cass finds there has been a break-in ... curiously, only some old papers are disturbed.

Then the body of a man is found in a cove close-by and while it looks to be an accident at first glance, suspicions are quickly aroused - and soon the police have a murder on their hands. At the same time, Cass begins to suspect Tamar knows more than she's letting on about her family's ties to the local laird. As the family start to gather, secrets won't stay buried for long ...