Don Winslow of the Navy #7

Commander Don Winslow takes command of a submarine with Lieutenant Red Pennington as first officer, tasked with a secret mission to proceed straight to Tokyo to scout Japanese activity and give the Allies something to worry about. While navigating dangerous waters, Don discovers evidence of a sinister Japanese invention on the sea bottom that could change naval power in the Pacific, which he risks his life to investigate. The main story, "Sea Ghosts," reveals a Japanese underwater device being used in the area, prompting Don and his crew to uncover this secret weapon while evading enemy contact.