The year is 1800, and Britain and France have been at war since 1798, in what later was to be known as the War of the Second Coalition. Gilliatt, a fisherman-turned-smuggler on Guernsey, agrees to transport a beautiful woman, Drouchette, to the French coast on his ship the Sea Devil. She tells him she hopes to rescue her brother from a French prison. Gilliatt finds himself falling in love and so feels betrayed when he later learns that Drouchette is a countess helping Napoleon plan an invasion of Great Britain. In reality, however, Drouchette is a British agent working to thwart this invasion. When Gilliatt learns this, he returns to France to rescue her, just as her true purpose has been discovered by the French.
The film was originally titled Toilers of the Sea, from the novel by Victor Hugo which formed the basis of Borden Chase's screenplay. The novel was changed substantially and Hugo is not credited; Borden Chase is given a credit for story and screenplay. The film was made by a British independent company, Coronado Productions, belonging to producer David Rose. The female lead was originally offered to Joan Fontaine who turned it down. She was replaced by Yvonne de Carlo, whose casting meant she had to postpone a film she was going to make for Edward Small, Savage Frontier. Her co-star was Rock Hudson, on loan from Universal; Hudson and de Carlo had previously made Scarlet Angel together. Rose arranged for the film to be distributed through RKO. The director was Raoul Walsh who had just made Blackbeard the Pirate for RKO. Filming started August 1952on location on the Channel Islands. There was also shooting in Saint-Malo, France. Walsh fell into the sea during shooting one scene and had to take two days off to recover. De Carlo was having an affair with Aly Khan during filming. Bryan Forbes plays Rock Hudson's sidekick. The role was meant to be played by Barry Fitzgerald but Forbes had befriended Walsh during the making of The World in His Arms which Walsh directed and Forbes appeared in. Walsh insisted Forbes play the role, and that Forbes help rewrite the part for a younger actor. Forbes later wrote: "The finished film now...reminds me both of happy times and, less agreeably, my ludicrous performance in a fairly ludicrous film." Richard Addinsell wrote the music.