Arson is suspected when a house burns to the ground following a gas explosion and a man and a woman are found dead. Wallander and the Ystad police investigate and uncover an intricate web of lies, betrayal and secret love affairs.

Wallander has become a grandfather and is trying to seize the role as good as it goes, because he wants to be closer to his daughter Linda and her family. When Linda's father in law mysteriously disappears, Wallander is drawn into the case that takes him back in time to the Cold War and the submarine violations in the Stockholm archipelago. At the same time he's starting to suspect that something is not right with him...