While on break from school, Takuya Arima, a student at Sakaimachi Academy, receives a package from his father who supposedly died months ago.

The package contains a round mirror and a strange object with glass beads fitted into it. Accompanying the package is a letter which leads Takuya to believe his father may still be alive:

“Take this device to Triangle Mountain on the Sword Cape at 10 PM.”

Determined to solve the mystery of his father’s disappearance, he follows the letter's instructions and heads to Triangle Mountain. There he encounters a beautiful woman lying on the ground, unconscious and dying.

She's not alone. Takuya is suddenly confronted by his father's old friend and a reclusive transfer student.

At that moment the ground rumbles violently and light envelops him... Takuya's journey through parallel worlds begins!