This is the story of a forgotten campaign: Next to nothing has been written about the U-boat war in the Indian Ocean. The battle began in August 1943. The Japanese allowed U-boats to use Malaysia as an operational station. From that base, they mixed with Japanese forces on a hitherto unseen scale: a move that spread the U-boat war throughout the vast Indian Ocean and into the Pacific. The joint action also gave U-boats the opportunity to penetrate the Pacific Ocean for the first time, attacking shipping off the Australian coast and hunting off New Zealand. Plans were even afoot for an assault on American supply lines. Stories of U-boats laden with gold and treasure stem almost exclusively from boats destined to and from Japanese-controlled Malaysia, laden with material exchanged between the two major partners of the Triple Axis Alliance.