Vigàta is bustling as the new filming location for a Swedish television series set in 1950. In the production frenzy, the director asks the locals to track down movies and vintage photos to faithfully recreate the air of Vigàta in that time. Engineer Ernesto Sabatello, while rummaging in the attic of his house, finds some films shot by his father from 1958 to 1963 – always on the same day, March 27; and always the same shot, the outside wall of a country house.
Montalbano hears the story and, intrigued by the mystery of it, begins to investigate its meaning. Meanwhile, a middle school is threatened by a group of armed men – but a closer look at the situation finds Montalbano looking into the students themselves, and finally delving into the world of social media.