Zatoichi is forced to kill a young man who owes a debt to a yakuza boss. Moments later, his sister Osode arrives with the money she earned (prostituting herself) to pay his debts. The bosses true motives are revealed and he attempts to steal Osode even though the debt is paid. Zatoichi realizes his grievous error and protects the girl from the gang. Osode and Zatoichi are caught in a dilemma as she must rely on her brother's killer for protection and Zatoichi wrestles with the injustice he has caused.
One of the nuns at Senjuan is Sister Shunko (Michiyo Yasuda). Unlike the usual nun, however, she often goes out to see the world, being of the opinion that nuns should not lead cloistered lives but should see something of modern life. She makes the acquaintance of a young girl named lkuko (Kayo Mikimoto) and saves her from the advances of a gangster named Goro (lchiro Nakatani). In the meantime she turns down several propositions and, in revenge, one of her admirers denounces her to the Mother Superior (Kuniko Miyake). This lady is of liberal views, however, and refuses to do anything about it. Then Shunko is visited by Goro's gang boss who wants lkuko back and says he will blackmail Shunko unless she agrees.
