Reversi is about a boy who comes in contact with a demon and gains the power of that demon. With those powers, he is able to transmit his thoughts and ideas into the minds of people he touches. The main character uses this power to make everyone have the same ideas that he has, thinking that if everyone thought like he did, the world would be a better place. The society catches on and the police get involved. A demon of light appears, who is one using the demon's power, but uses it in a way opposite the anti-hero of the manga, by returning the already brainwashed people back to normal.