After escaping from a penitentiary on the island of Elba, five convicts led by The Baron enter the office of an iron mine and demand the payroll. Carlo, the mine owner's engineer son, refuses. When Carlo's sister Anna and friends Susi and Giulia come upon the criminals, Susi tries to summon help. Furious, the psychotic Negro convict Luca overpowers Susi and attempts to rape her. During their struggle Susi shoots Luca in the arm. In retaliation he murders her. Alarmed, Carlo hands over the checks, which The Baron orders his minion Toni and hostage Anna to cash. At the bank Anna endorses a check with a plea for help. As Toni returns, Luca, having slain The Baron in his absence, opens fire. Upon arrival the police discover both convicts dead and the wounded Carlo in Giulia's embrace.
