Seno Soichiro is a ronin trying to live quietly in Edo, but trouble always finds him. Despite trading his blade for one made of bamboo, challengers still seek him out. After taking up residence in an Edo tenement, Seno forms an unlikely bond with Kankichi, a young neighborhood boy. But a serial killer haunts the neighborhood, and Seno may be the only one who can confront what lurks in the dark.