[1] A 1957 film starring Robert Mitchum and Curd Jürgens was based on the novel, but with major changes to characters and action, including making the destroyer an American ship.

John Murrell, Captain of the Hecate, proves himself a match for the wily U-boat Kapitän von Stolberg, a man from an aristocratic background who is not enamoured with the Nazi regime.

The submarine, badly damaged and critically short of air and battery power, is forced to the surface, and a gun battle takes place.

The novel is divided into five major sections, which reflect the nature of the conflict between the U-boat and the destroyer: Radar Sparring, ASDIC Duel, Gun Battle, Cold Steel, Fisticuffs.

In an introductory note, the author points out that the story is fictional; as far as he is aware, no British destroyer ever fought a single-ship action against a U-boat.

He further explains that, in such an action, the odds are rather more in favour of the submarine, which has more chances of sinking her adversary by torpedo and deck gun, whilst presenting a smaller target for the destroyer.