Beat the Devil (1953) Humphrey Bogart, Jennifer Jones, and Gina Lollobrigida

Billy Dannreuther is a formerly wealthy American who has fallen on hard times. He is reluctantly working with four crooks: Peterson, Julius O Hara, Major Jack Ross, and Ravello, who are trying to acquire uraniumrich land in British East Africa. Billy suspects that Major Ross murdered a British Colonial officer who threatened to expose their plan. While waiting in Italy for passage to Africa, Billy and his wife Maria meet a British couple, Harry and Gwendolen Chelm, who plan to travel on the same ship. Harry seems a very proper and traditional Englishman, while Gwendolen is flighty and a compulsive fantasist. Billy and Gwendolen have an affair, while Maria flirts with Harry. Peterson becomes suspicious that the Chelms may be attempting to acquire the uranium themselves. Though this is untrue, it seems confirmed by Gwendolen, who lies about her husband and exaggerates his importance.