Franco Sereni, a captain of carabiniers, is dismissed from service for being the proponent of "the law of the gun". He is asked to hold a private investigation of several cases of blackmailing wealthy women. Soon Sereni finds out that there is much more then just blackmailing.
Convict Roberto murders a guard and escapes from jail with his cellmate. Once free he joins a group of gangsters and becomes a professional hitman. The gang abduct a young woman and when one them attacks her, Roberto shoots him and takes her to an abandoned farm house…..
Tina is on trial for the murder of her lover, Gino. The violent nature of their relationship, revealed in the trial, seems to make obvious that she accidentally killed him during a fight. The lone female jury member compares her life to Tina's and, believing her to be innocent, sets out on her own to find a missing witness that can prove Tina's innocence.
