When a man is found murdered with a sawn-off shotgun, Vigata police are called upon to extinguish what appears to be the beginnings of a new Mafia war. But Montalbano has his doubts on the exact nature of this particular murder. When he is taken off the case and assigned to investigate the disappearance of a young Ukrainian woman, he gradually uncovers a series of links between the two cases.

One of Montalbano's most difficult cases begins during one of his habitual morning swims, when he finds a decomposed body floating in the water. The investigation leads him to uncover the unsavoury realities of international child trafficking.