In order to claim his billion-dollar inheritance, Guido 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 female detective Rosie Jones (Valerie Perrine) to prevent Guido claiming his inheritance.

[5] The film was the idea of Dino de Laurentiis, who wanted to introduce Italian actor Terence Hill, at that time one of the biggest movie stars in Europe, to American audiences.

Kaplan later stated the production was difficult - he wanted to cast Lily Tomlin but Fox insisted on Valerie Perrine.

[6] In a retrospective review, the critic Keith Bailey called it "yet another case of Hollywood bringing a foreign actor in, and getting him to do different material than what made him famous in the first place".