Jason Fister (Dustin Hoffman) is the Internal Revenue Service agent sent to Rome to investigate the hidden money of the late gangster Mike Madigan (Cesar Romero). Jason meets Vick Shaw ( Elsa Martinelli) and he mistakenly takes her to be the dead mobster's mistress when in fact she is his daughter. Soon underworld thugs converge on the couple in an attempt to steal the stolen loot.