Yuko Asou is a schoolgirl in late 1980s Japan who is fated to protect three different realms – our own Earth, the land of spirits, and Vecanti, the Dream World – by wielding a mystical sword known as Valis. Demon lord Rogles extinguishes a light in Vecanti which functions as a source of power for those who live there, and in a desperate plea for salvation, its queen Valia reaches out for a brave soul who can help them in their time of despair. Yuko on Earth is the one who answers the call, being summoned by magical forces into Vecanti to liberate them from the evil of Rogles.