When a smuggled shipment of heroin is hijacked, Marcos Aristoulas is threatened with murder by the Mediterranean Syndicate if he fails to retrieve it. He meets embittered ex-convict and former INTERPOL agent Harry Bell in Madrid and enlists his aid. In Barcelona, Harry meets Jill, a hippie who agrees to help him. Upon learning that the heroin is in Rome, Harry and Jill leave for Italy, followed by Max Mainzhoffer, an INTERPOL agent. Max is found murdered by the syndicate, but Harry apprehends the thief and killer--Sonia, Marcos' girl friend who was responsible for doublecrossing Harry and sending him to prison. He kills her, finds Jill dead, and returns to Athens. He informs Marcos that the heroin has been turned over to the authorities. His deadline passed, Marcos is murdered by a syndicate member.