Short, lean, compactly written novel concerning a single combat engagement in what is supposedly an untenanted part of the Atlantic, between enemy ships- a destroyer and a submarine-Captain vs Kapitan, men of equal skill and determination. Symbolically, the Captain of the British destroyer ""Hecate"" is playing chess when his radar alerts him to a submarine ahead. Almost simultaneously the Kapitan of the German submarine is warned of what seems a false echo trailing him to his goal, the armed cruiser ""Cecile"". The British captain's deadly calculations are based on exact knowledge of how and why a U-boat will manoeuvre, how and where her radar can detect the echo as another boat, under what circumstances she can place her torpedo. The German, accustomed to the illogic of the enemy, cannot believe it is a real menace, but his instincts too are sound, and eventually a depth charge from the ""Hecate"" and a torpedo from the U-121 precipitate battle. For 40 hours it is one against the other and in the end both win- both lose- both ships go down. The maritime conundrums will find absorbed readers; the authoritative background will appeal to Navy personnel.