In this seagoing military drama set in World War II, Lt. Comdr. Ericson (Jack Hawkins) is made captain of a British corvette, a small escort vessel used to guide and protect convoys traveling through the Atlantic. Ericson had his confidence severely shaken during his last command, in which he lost his ship and most of its men following an attack by a German U-boat.

As he leads a new and largely inexperienced crew aboard the H.M.S. Compass Rose, Ericson is once again thrown into a life-and-death dilemma that forces him to choose between destroying an enemy ship and sparing the lives of his own men. The Cruel Sea featured breakthrough early performances from Denholm Elliott and Virginia McKenna, and it was based on a best-selling novel by Nicholas Monsarrat, who stipulated that the film rights could be sold only to a British company.