Set in a virtual simulation of Shibuya, Tokyo which is regulated by an entity named Piece which does not allow inhabitants to live, the series focuses on a fifteen-year-old boy named Tsuyoshi who seeks to find both his lost memories and a way to escape Shibuya. To maintain control, Piece locks "kills" those who do not operate within the proper confines of the world, which results in their being reset and inserted back into the city with a new name and identity and without their previous memories.