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...

Kurt returns to work after a temporarly suspention. At the same time a girl disappeares which draws in the entire Ystad police and military looking frantically for her. When Kurt starts to work on the case, he begins to see similarities to a case he worked on ten years earlier, which hit him very personally.