Early one New Year's morning, the rounin Senou Souichirou appears in Edo's Katagi tenements.
Initially, the inhabitants regard him with fear and suspicion: Kankichi, the carpenter's son, thinks he may not be human; the neighborhood cats remark that he reeks of blood. But soon Souichirou pawns his sword, and, with a bamboo replica at his waist, settles down to a quiet life as the neighborhood school-teacher.
Months pass, and all appears to be well. But trouble will not leave the Katagi tenements alone …
