A murder. The body of eighteen-year-old TV personality Kathleen is found abandoned on a remote beach at the head of An Loch Dubh - the Black Loch - on the west coast of the Isle of Lewis. A swimmer and canoeist, it is inconceivable that she could have drowned. A secret. Fin Macleod left the island ten years earlier to escape its memories. When he learns that his married son Fionnlagh had been having a clandestine affair with the dead girl and is suspected of her murder, he and Marsaili return to try and clear his name. A trap. But nothing is as it seems, and the truth of the murder lies in a past that Fin would rather forget, and a tragedy at the cages of a salmon farm on East Loch Roag, where the tense climax of the story finds its resolution.