The plot of Beat The Devil involves a band of four motley characters intent on stealing uranium from British East Africa for a quick profit, in a land deal brokered by the Bogart character,(named Billy Dannreuther). The story begins in an Italian seaport as Bogie and his wife Maria, played by Gina Lollobrigida, wait on the arrival of the four criminals played by Philip Morley (Peterson), Peter Lorre (Julius O'Hara), Ivor Barnard (Maj. Jack Ross), and Marco Tulli (Ravello). From there they plan to sail to Africa. While waiting they meet a British couple going on the same ship, Edward Underdown and Jennifer Jones (who play Harry and Gwendolyn Chelm).

The plot is an afterthought though. The film is about eccentric behavior. Philip Morley's character Peterson is a nervous, greedy, bumbling fellow. The two wives develop crushes on each other's husbands. Jennifer Jones as Gwen Chelm is a flighty, happy, imaginative creature of fancy who falls in love with Bogart.
The sea captain is a drunkard, and the ship is a rust bucket with a failing oil pump. The steward tells the passengers to return to the lounge. "We're heading to the nearest port, and there seems to be some chance of our making it" he says smiling.

If you enjoy relaxed, amusing entertainment, you might like the witty company of this cast of seasoned actors and beautiful actresses.

An unlikely group of would-be swindlers find themselves stuck in Italy when their boat (to Africa) breaks down. Theoretically, the four are on their way to sell vacuum cleaners (but really to pick up some ostensibly worthless land - that only they know is a rich source of uranium). Whilst they wait, they meet a British couple and soon the six, somewhat distrustingly, continue their journey. The story isn't really up to very much. It's the characterisations that work well. Humphrey Bogart is great as the seedy but clever foil to the excellent Robert Morley - both make good use of the witty script from Truman Capote and direction from John Huston. Peter Lorre, likewise, always manages to make less look like more - his eyes, shrugs and smiles add much that do not need accompanying words. Gina Lollobrigida rarely made a good film, I think, though. Glamorous, sexy - sure, but talented? I think not - and here she adds very little, unlike Jennifer Jones ("Mrs. Chelm") whose ability to spin a yarn or two would stretch the imagination of Enid Blyton. It runs out of steam a little towards the quite quirky end, but is still a well structured and engaging adventure with just a hint of romance.