Marshal Rocca goes to Rome to attend the funeral of a cobbler friend and here he meets Benedetto with his wife Elisa, his old flame. Back in Viterbo, he begins to investigate the murder of a gas station attendant's son, which appears to be connected to two robberies. Meanwhile Rocca receives a visit from Elisa, who disappears after revealing that she is in crisis with her husband; Benedetto also arrives in Viterbo in search of his wife, whose car is found in a ditch. A woman friend of Elisa's is then found dead, who could be connected to the robbery and who also turns out to be the sister of a man arrested years earlier by Rocca because he was found guilty of killing a music teacher, loan shark and paedophile; he too is found dead in a farmhouse from the wounds sustained in one of the two robberies. Meanwhile Benedetto attempts suicide after the discovery of Elisa's body: the marshal will save him.