An attractive woman appears dead wrapped in a para-glider, what at first looks like a sports accident will quickly turn into murder. Commissioner Cassandre will have friction with the prosecutor, who is the mother of her captain.

An educator of the institute for young people with problems where Jules, Cassandre's son attends, is murdered, it seems that she had discovered something about the death of the mother of a classmate of the boy years ago.

In the high mountains, a couple and their daughter are shot dead, the girl, Olympic biathlon champion, survives, Cassandre and her team will investigate the dead father, famous mountain guide whom Lieutenant Nicky Maleva knew.

Someone tries to assassinate Dr. Meyer days after his wife dies, instead Captain Roche is shot, in the investigation of the event, a stepdaughter of the Dr. appears with whom Roche had an affair years ago and whom everyone considered dead.