Rui Kamishiro is a young criminal who was sentenced to 20 years for the murder of several people and illegal possession of weapons/dangerous devices. Even though it was an accident, he knew that sooner or later he would be caught, so he did not resist the court for a long time and went to prison. He is often very bored there and can shirk work or irritate the workers and other prisoners. Many consider him crazy, even though he can look normal. He was given a new neighbor, Tsukasa Tenma