In 2002, the Marine Express, America's and Japan's first underwater train, is poised to launch its inaugural voyage. The chief engineer, worried that the test run will be exploited for illicit purposes, hires private detective Ban Shunsaku. When Shunsaku arrives at the engineer's mansion, he discovers the man has been murdered, leaving only a fleeting glimpse of the killer’s face. Armed with that fragment, Shunsaku boards the Marine Express to investigate the crime, only to find that the train itself holds secrets far beyond anyone’s imagination.
