Yusei Gakuen is a boarding school locating on the top of hill. Show Hamura transfers to Yusei Gakuen and meets his twin brother, Kai Mizou. He is a little twin brother who was separated when they were children. But Kai lost his memory unlike Show who has Kai's memory. Kai is cautious about Show because he knows what Kai doesn't know. One day, a principal Reiya calls both and asks them to look for Nagisa who is missing. Both joins to Anri, Chris, Shion, Sena and ahead to an abandoned building. Suddenly, monsters show up and attack them. Will they be able to find and save Nagisa?