Signor Lapecora, a respectable elderly man, was found murdered in the elevator of an ordinary residential building in Vigate. It turns out that he had a mistress, the beautiful Tunisian Karima. The case seems quite ordinary, but Montalbano, as always, plunges headlong into it. The Commissioner has difficulty getting rid of another investigation into which they are trying to drag him: on a fishing boat sailing from Mazara to Vigata, a Tunisian patrol boat accidentally shot and killed a Tunisian fisherman. A meeting with the mysterious “school lunch thief” radically changes both the course of the investigation and the very life of Commissioner Montalbano.