A plot that has the rat-a-tat pace of a Thirties pulp. During the first days after the bomb was dropped on Nagasaki, some Japanese businessmen condensed their empires into four cannisters of diamonds and sent them along with some art objects to a secret place by way of a submarine--but the sub sank. Recently, the diamonds were recovered and while being transferred by plane were again lost when the plane went down. Now Daniel Chase, a master diver and underwater engineer, and John Hyland, an aeronautics expert, have been kidnapped by Mr. Inahara, a big, bristly, supremely gifted Japanese who wants them to help him recover the diamonds. Also along is Lynne Webster, wife of a British marine biologist who may be dead, or may not be. Either way, her safety adds charming leverage to Mr. Inahara's manipulations. The tale is full of Hawaiian and Micronesian atmosphere, gas guns spraying hotel rooms, submachinegun chases in cars, small-boat battles at sea, and the climactic nightdive to the sunken sub (not the plane), which reveals itself to be not Japanese but American of far more recent vintage. A traditional shoot-'em-up with no new twists, but nothing interferes with the story's greased slick as the heroine slides arm-first into a crocodile's mouth. That shakes you up!