When an arrogant old samurai refuses to let Iemon marry his daughter Iwa, the young samurai kills kills him and and his two companions. With the connivance of his servant Naosuke, Iemon claims the assassin was a local bandit. He promises to help Iwa avenge her father's death. They set off in search of the culprit, accompanied by Iwa's sister, Sode, and Yomoshichi, the son of one of Iemon's other victims. Naosuke, attracted to Sode but apprehensive of the closeness between her and Yomoshichi, stabs the young man and, with Iemon's help, throws the body into a waterfall. The two conspirators claim that Yomoshichi was killed by the same bandit responsible for the old samurai's death. They persuade the sisters to split up to continue the search. Two years later, unknown to the two sisters, both couples are in Edo. Iemon has married Iwa and has an infant son, but they live in poverty. Naosuke, eking out a living selling patent medicine in the streets, lives with Sode, but has promised he won't sleep with her until her father's death is avenged. He and Iemon meet secretly in the local brothel, where they plot to become wealthy. They stage the rescue of the wealthy Ito and his daughter Ume from a gang of ruffians. In exchange for money, Naosuke promises Ito he'll arrange Iemon's marriage to Ume. To be rid of Iwa, Iemon bribes a local masseur, Takuetsu, to seduce his wife. He also gives her a poison obtained by Naosuke. The poison disfigures Iwa horribly. Before she dies, Iwa learns of her husband's treachery. Rather than leave her infant son in the care of such a father, she kills the child before herself dying. To silence Takuetsu, Iemon kills him, too. The two corpses are nailed to either side of a shutter and dumped into a deep pool by Iemon and Naosuke. Iemon marries Ume, but on their wedding night sees visions of the disfigured Iwa and Takuetsu. Deluded by the visions, he kills Ume and her father, then flees to a temple for protection. Naosuke taunts his master, and is killed by Iemon. Sode is led by her sister's ghost to Yomoshichi, who has survived the attack two years earlier. Together they hunt down Iemon and avenge his victims.—Roger Keightley