According to legend, a demon is imprisoned inside the Masaki Shrine in Kurashiki, Japan. When Tenchi Masaki, a student at the local high school and grandson to the shrine master, accidentally breaks the "seal", he discovers that it is not just a legend!

Awakened from a deep sleep, Ryoko, the demon, in the form of a beautiful young girl, furious to discover she has been imprisoned for over 700 years, launches an all-out attack on Tenchi. Using her amazing powers, including flying through the air, moving through walls, and hurling massive bolts of electrical power from her hands, she pursues Tenchi in a terrifying midnight chase throughout the school.