A supermarket is attacked with explosives. Two former employees are traced. Sabina Corsi and her boyfriend accidentally set fire to a classroom while smoking and are suspended from school. Ingargiola solves the mystery of his alleged paternity. An antique dealer is paralyzed during an attack. Corsi sets a trap for the killer. Tiberio has a heart attack while chasing a mugger. Corsi realizes that Carla Monti is implicated in Angela's murder but it will be difficult to frame her.