An aging samurai seeks revenge on the men who drove his son-in-law to suicide.

In the 17th century samurai who have been left without a livelihood as a result of the centralization of political power roam the countryside, appealing at clan estates for permission to commit harakiri, hoping that the clans will give them employment or alms rather than see them die. Hanshiro Tsugumo visits the Iyi estate in Edo and asks for such permission. As a warning Kageyu Saito, the clan's chief retainer, tells Hanshiro of Motome Chijiiwa, a young samurai who earlier came there with an identical request. To prevent the debasement of the samurai code, the young man's bluff was called and he was forced to go through the harakiri ritual, though he carried only a bamboo sword. Hanshiro, undeterred, asks in turn for each of the clan's three principal swordsmen to act as his second in the harakiri ritual, but none dares appear. Hanshiro reveals that he was Motome's guardian and father-in-law. He explains that Motome had sold his sword, desperately trying to provide for his wife and child, who have since died. In his plan for revenge Hanshiro has waylaid the three swordsmen--who were responsible for forcing Motome's suicide--and has dishonored them by cutting off their topknots. Kageyu orders his men to kill Hanshiro, but the old samurai, in a furious battle, kills and wounds many of Kageyu's men before he dies. Kageyu orders his three retainers to commit harakiri and decrees that what has occurred must remain a clan secret.