Zatoichi, traveling by palanquin, comes across a struggling mother, Otoyo, and her infant son. He offers her he palanquin to make her journey quicker. However, a group of ronin who had been pursuing Zatoichi for the bounty on his head attack the palanquin, thinking him to be in it. Otoyo is killed, but the son survives. Zatoichi feels duty bound to deliver the baby safely to his father in Miyaki, a sixty mile journey.

Along the way, Zatoichi meets a traveling prostitute, Ko, who follows Zatoichi because he is lucky with gambling. After Zatoichi hires her to help care for the child, she begins to repent of her lifestyle and longs to remain with him and the child. When they arrive at Miyaki, Zatoichi discovers that the late woman’s husband, Unosuke, is the local yakuza boss, and is engaged to be married to the daughter of another prominent boss. Unosuke had let Otoyo be taken away as collateral for a loan, and he had no intention of receiving her back. He dismisses Zatoichi and refuses to take the child.

Zatoichi dismisses Ko, not wanting her habits to influence the child. Zatoichi is resolved to raise the child himself, but is gently dissuaded by a priest to leave him at the temple, lest he grow up to be a yakuza like Zatoichi. Meanwhile, the ronin who were pursuing Zatoichi convince Unosuke to join their plot. They meet Zatoichi in the woods and attempt to confuse him with torches. Zatoichi manages to slay the ronin and slays Unosuke after extracting an apology for his treatment of Otoyo. Zatoichi leaves the boy in the charge of the temple and departs.