Since quite a while past, Tenjo Yuuta has consistently been harassed. He goes to secondary school while living alone at his late granddad's home. Despite the fact that he was constantly met with serious tormenting, he discovered comfort during the extended vacation break. During this time, while cleaning his granddad's home, he additionally chose to tidy up the room where his granddad keeps the things he gathered for the duration of his life. A room where Yuuta has never entered. While attempting to put together the things gathered by his granddad, he tracked down a strange entryway that was apparently removed from the divider. Wondering for no specific reason, he opened it. And afterward...