In 1995 Tokyo, a teenage boy seeking romance follows a fortune teller's guidance to a remote museum, where he meets a girl only to have their encounter interrupted by an earthquake. In desperation, he speaks an incantation meant to win her heart—but instead accidentally breaks an ancient seal and releases a demon that seizes control of his body, trapping his consciousness in the creature's withering form. Pursuing the possessed entity to the home of Dr. Simon, a reclusive physicist, the boy discovers the scientist possesses a time machine called the Time Belt, which the demon steals and uses to flee into the past. Caught in the temporal wake of the escape, the boy is pulled backward through time alongside his demonic captor, setting the stage for a desperate chase across history to reclaim his body and undo the catastrophe he has unleashed.