Kyo-ui is a young man with an absent gaze, withdrawn into himself. Many call him "the retard". In the city, he survives thanks to small tricks and other sales of heterogeneous objects.
One day, he witnesses the assault of Jun, an escaped prostitute, by members of the Mohaiga sect.
For a moment, Kyo-ui seems to be a different person, but he overwhelms the assailants.
The girl is then "recovered" by Jingaku, a mysterious samurai who will save her and Kyo-ui from a second confrontation with the killers of the sect.
Without them realizing it instantly, they all put their finger in an infernal spiral.