Four female students committed suicide, one after another. This shocking incident made some students unscrupulously excited. Before anyone knew it, it was rumored that the girls were cursed and killed by one of the seven school mysteries, the Spirit of the Old School Building. For many students, it was just silly gossip. One of such people was Saeki Yashiro. Still, for a certain reason, he could not ignore it. It was because after the four girls had died, he started to have a strange nightmare. Lacking a good night's sleep, Yashiro gradually weakened day after day without even noticing it. At that time, one person appeared before him. That was a strange girl named Velvet. She told him... "...You are cursed."