Commander David Smith, a mere youth, has already committed one indiscretion too many. After being wounded at the WW I Battle of Jutland, he's been heard commenting that the British should not even have been at that battle. And there is something about a woman, nobody knows just what, but it's enough to have Smith transferred to the nether regions of the Navy. . . offshore of Chile! There he is second-in-command of H.M.S. Thunder, in a Germanless ocean as far from the War as possible. But Smith's captain falls sodden with gin from a ladder and dies. Then, answering an S.O.S. from shore, he finds himself fired at by a British lady spy, Sarah Benson, before he has even introduced himself. Indeed, though he takes her aboard, he never does find out why she killed the man standing beside him. Then the big news breaks, that Germany does have two ships in these waters, Kondor and Wolf, whose object is to sink H.M.S. Thunder and take control of the South Pacific. Thunder is no match for these two giants, but eventually must take them on. Not only does Smith outwit his German counterparts, but he manages to stay afloat despite direct hits upon his own ship, and despite casualties of over 150 dead or wounded. At the moment of victory, a third German ship appears and bears down on Thunder, preparing for the coup de grace. The Mata Hari stuff is fairly foolish and a bit confusing, but otherwise this is a strong and vivid enough war-at-sea voyage for fans of the genre.