Masahiro Setagawa has stopped believing in heroes as he believes that heroes do not truly exist, especially since he has been getting into a lot of trouble. He's been coerced into joining a gang and is often bullied and used as a gopher boy. However, soon an infamous street fighter named Kousuke Ooshiba, or the "Bear Killer" inadvertently saves him. This man happens to be the older brother of his best friend Kensuke Ooshiba and his current homeroom teacher. Now Kousuke has claimed Masahiro as his "underling" and promises to protect him, but the feelings seem to run far deeper for both. Meanwhile, Kensuke is reunited with an old friend Asaya Hasekura, a popular pretty boy who declares his love for Kensuke and leaves Kensuke confused and unsure.