Hikari 109, a Japanese high-speed train--or "bullet train"--has been sabotaged. A madman has rigged it with a bomb that detonates if the train slows to less than 80km/hr. The madman insists that the authorities pay him five million dollars for instructions on how to diffuse the bomb and save the lives of the 1500 passengers. The authorities must now somehow clear the way for the train, keep the passengers calm, try to locate the bomber, and try to determine whether there is really a bomb on the train. The film is relentlessly suspenseful, and has enough twists to keep you guessing all the way to the end of the line.