Conan and his friends search for a foreign spy who might have also committed a murder.
The movie is set on a state-of-the art Aegis vessel with the full cooperation of Japan's real-life Ministry of Defense and Maritime Self-Defense Force. The corpse of a Self-Defense Force member has been found — minus the left arm — and a spy has infiltrated the Aegis vessel. The heroine Ran is put in jeopardy, and Conan is forced to stand up against the dangerous Spy "X."