Don Winslow of the Navy #27

Don Winslow fights off enemy agents attempting to destroy a ship's transmitter and warn an island, then pursues them to prevent them from reaching a gambling ship where they plan to rendezvous. Using a membership card as cover, Winslow infiltrates the gambling vessel and must stop the enemy operatives from escaping with crucial information. The story involves naval combat, hand-to-hand fighting, and espionage aboard the gambling ship as Winslow works to thwart the enemy plot.