Wallander forgets his gun in a bar and is suspended. With time on his hands, he looks into the disappearance of his daughter's father-in-law who may have been involved in the death of a young sailor during an international incident back in the '80's with a submarine entering Swedish waters.
A girl disappears on her way to school, and suspicion falls on her father who has been fighting for her custody. Wallander's investigation is helped when he visits a woman whom he had arrested when her own daughter disappeared.
When a teenage girl is found dismembered, Wallander has to investigate the milieu of human trafficking. However, because of his memory loss, he is not in charge; Martinsson is, and the two do not agree on who the culprit is.