Published in Thrilling Comics #1, Feb. 1940 - 16 pages.
Jim Fulton, the inventor of the Fulton submarine, insists that only America will have access to the plans for his new submarine but a foreign agent is determined to get them. The spy overhears Fulton explain how three gold coins, put together, will reveal where the plans are hidden. Then Fulton's daughter is kidnapped but Nickie Norton is already on the case. After that, the story goes haywire with action moving to Mexico where an Irish inspector gets help by Norton chasing down the spy leading to a fight with a submarine.