Past lives, parallel worlds, magical powers. Chiyo, the heroine, had never really thought about them.
She lived a quiet life with her parents, until one day, while looking for a pack of bottled water in the basement, she discovers strange stuffed animals. After taking one of them, she feels something pushing her toward the door locked by her father and loses consciousness. As she comes to her senses, Chiyo doesn't recognize the family basement and realizes that she is not in her world anymore!
Between demons and magicians, Chiyo will have to choose a side.
To make things worse, the one who will decide her fate is none other than... The Devil himself!