Guido Falcone (Terence Hill), an easygoing Italian mechanic, is heir to a billion-dollar inheritance after his uncle dies in a freak accident. In order to claim his inheritance, he must reach San Francisco within twenty days to sign a document. His uncle's greedy assistant John Cutler (Jackie Gleason) wants the money for himself, and hires a female detective (Valerie Perrine) to prevent him from reaching his goal.