An ex-Vietnam vet is forced to become a hit-man and gets caught in the middle of a conspiracy.

Bruno Fioretti, known as "Mandrake", is an inveterate gambler who never misses a day at the horse racing track in Rome. He is doubly unlucky: he bets too much on one horse, and his wife is sleeping with his best friend because Mandrake is always at the track. Penniless and cuckolded, Mandrake decides to make one last bet.