Mochizuki Kotarou is a highschool student who dreams of being a somebody, but is too weak to try to achieve greatness. One day he is caught in a fight and a Samurai spirit takes over him and wins, the spirit's original owner was named Mochizuke Kotarou as well.
The male protagonist is someone who follows his own moral. By reason of fair play and well being of his friends, he is not afraid to talk or do whatever he thinks right. Not obeying the school rules, he is always at verge of punishment.