Jihei, a paper merchant in Osaka’s Tenma neighborhood, Osan is his wife, and he carries on an affair with Koharu, a popular courtesan Shima Iwashita. He has promised twenty-nine times to free Koharu from her five-year contract at the Kinokuni brothel, but the money he needs—ten kan of silver—keeps slipping away. Koharu longs to leave prostitution and begs Jihei to end the arrangement, while Jihei warns that if she dies, he will end his own life as well; together they hatch a plan for shinjū.
When Koharu returns to the Kinokuni brothel, a rich merchant named Tahei Hōsei Komatsu arrives, offering to pay whatever it takes to free her. Koharu accuses Tahei of spreading rumors about Jihei’s wealth, and Tahei tells Koharu’s madam that Koharu has another client for the night, a samurai. The samurai arrives, Koharu explains her contract and her plan to die with Jihei, and the samurai discourages suicide, pledging to help Koharu pay off the contract, and the two head to bed.
Tahei leaves a bar, loudly boasting about Koharu’s supposed samurai client. Jihei overhears and goes to the Kinokuni brothel to confront Koharu, where he overhears Koharu and the samurai in conversation. In a fury, he tries to stab the samurai through a window, but is restrained. The samurai ties Jihei’s arm to the window and departs. Tahei stumbles upon Jihei tied up, mocks him as a thief, and the samurai rebukes Tahei for his lies, urging Jihei to strike Tahei—an act that Jihei carries out. A mob then chases Tahei from town.
Back inside the teahouse, Jihei discovers the samurai is his brother, Magoemon, in disguise. Jihei begs for forgiveness and chastises Koharu for cheating on him. Magoemon reveals that Osan’s father, Gozaemon Yoshi Katō, is angered by Jihei’s affair and intends to reclaim Osan. Jihei vows to leave Koharu behind. Magoemon finds a letter to Koharu from Osan’s mother but says nothing to Jihei.
A few weeks later, at Jihei’s home and paper shop, Osan’s servants Otama Unko Uehara and Sangoro Makoto Akatsuka arrive with Jihei’s children, Kantaro Shinji Tsuchiya and Osue Kaori Tozawa. Otama mentions that Magoemon was seen heading toward the shop with Osan’s mother Shizue Kawarazaki. Osan wakes Jihei, who pretends to work, while Osan’s mother arrives with Magoemon and shares that a rumor says a wealthy Tenma merchant will free Koharu in a few days. She suggests Jihei is the one, but Jihei insists it must be Tahei. She consoles Jihei but warns Gozaemon will not be easily convinced. Jihei gives her a written oath that he is no longer involved with Koharu, and she leaves.
That night, Osan finds Jihei in tears. She fears he still loves Koharu, but he insists he does not. Osan confesses she wrote a letter to Koharu begging her to betray Jihei so he would get over her, fearing Koharu might kill herself now that Jihei has left. The two realize they need 150 ryō to buy Koharu’s freedom. Osan unlocks a secret stash, giving Jihei 80 ryō, and she strips to pawn the remainder of 70 ryō. Just as Jihei is ready to go, Gozaemon arrives and orders a divorce letter from Osan. Jihei refuses, Gozaemon drags Osan away, and Jihei collapses in tears, crashing the shop’s contents in a storm of despair.
Jihei tracks Koharu back to the Kinokuni brothel, and they run to a graveyard where they make love. Afterwards, Koharu urges Jihei to kill her right there, then themselves elsewhere, arguing they should not die together since Jihei is still married to Osan. Jihei cuts off his topknot, which he says makes him a priest, thus nullifying his marriage to Osan, and Koharu unbinds her hair and proclaims herself a nun. The Daicho Temple bell tolls at dawn as they flee into the wilderness; there, Jihei kills Koharu, unties her obi, and uses it to hang himself with help from kuroko on a lone torii. The final shot returns to the couple lying opposite each other on a mat beneath the bridge, just as they were at the film’s start.
