Seventh volume in the Victorian British naval series featuring Lieutenant St. Vincent Halfhyde. The story of villainous Sir Russell Savory--whom Halfhyde captured after Savory tried to sell naval secrets to the Germans--continues with Savory in irons and homeward bound aboard the flagship Halcyon. As they round Cape Horn back into the South Atlantic, Admiral Daintree is worried that von Merkatz' small German fleet (which is pursuing their squadron) will crowd his ships onto the rocks along the coast of Tierra del Fuego. Also on board are Detective Inspector Todhunter, who arrested Savory and must return him to Scotland Yard; officious Foreign Officer Petrie-Smith; and that bombastic vast blob of snobbery, Flag Captain Watkiss, who is ready to meet von Merkatz ""with force and gunfire, by God! . . . we open fire and sink the bugger!"" So Daintree and Petrie-Smith must keep blithering Watkiss in check or there'll be war with Germany. But the real action gets underway when the Uruguayans have a revolution, throwing the British ambassador into jail. Can the ambassador be rescued? Daintree thinks Halfhyde might be just the man to do it. Through misreading a chart, however, Watkiss makes three of his ships collide, leaving the German squadron free entrance to the River Plate, where von Merkatz enlists the Uruguayans in recovering Savory. Meanwhile the ambassador is killed, and the Germans capture drunken Master-at-Arms Titmuss (in charge of Savory) when he falls overboard. And so it goes in a game of inventive sea-chess, pawns passing from side to side until Halfhyde sweeps into a Uruguayan fort and recovers Savory and Titmuss. Moderate fun--but it's time for some new ingredients in this series and for Halfhyde to expand beyond a straight man who gets one turn of derring-do per novel.