Commander Don Winslow is returned to the Office of Naval Intelligence from his command of his cruiser to investigate strange events on the Pacific island of Tangita, noticeably a ship being torpedoed. He discovers that there is a ring of saboteurs and enemy agents who are trying to destroy ships carrying supplies to the troops stationed in the islands and sabotage the war effort. Though the US Navy is preparing to build a naval base on Tangita, an unknown foreign power secretly has a subterranean submarine base beneath the island with the goal of preventing the American base from being completed. He sets out with three assistants to find the mastermind behind the activities.
The serial was based on the comic strip by Commander Frank V. Martinek, which was approved by the US Navy.[1] The strip gained new meaning with the approach of World War II, which would also affect the serial: "Its presentation as a Universal serial in October 1941 - just before the infamous attack on Pearl Harbor in December - was one of the most timely contributions of the serial field."[2]
The Universal serials for 1941-42 were meant to run: Riders of Death Valley, Sea Raiders, Head Hunters of the Amazon, Gang Busters. Head Hunters of the Amazon was, however, dropped in favor of this serial. This is possibly due to the greater name recognition of the licensed property over the more generic planned serial.[3]
