The story revolves around Munezo Katagiri, a lower caste samurai during the end of the Tokugawa period. His family falls on hard times after his father takes responsibility for the failure of the Goken Bridge project by committing seppuku. The film begins with Katagiri and his friend Samon Shimada seeing their friend and fellow samurai Yaichiro Hazama, off at the docks, with Katagiri having a bad feeling about Hazama's fate in Edo. Shimada marries Katagiris younger sister Shino. Kie, a servant girl from a farm who came to the Katagiri family at 16 to learn deportment, cooking, and other arts in order to prepare to be a bride also soon marries Iseya, a merchant. Three years later, Katagiri runs into Kie on the street. He is worried about her because she looks thin and pale and says she has just recovered from a long illness. When asked if she is happy, she does not answer, leaving him wondering if she is living well. Katagiri and his fellow samurai are being taught about the new weapons and military tactics imported from the Western World. They have a hard time adapting. The older samurai feel that fighting with firearms is without honour and goes against tradition. The military instructor complains bitterly of having to train "backwater village samurai." Katagiri hears from his sister that Kie has been sick and in bed for two months and that she has been treated very badly by her husbands family, even refusing to get a doctor for her. Angered by this news, Katagiri goes to the merchants house and demands to see Kie. When he finds Kie in a dark and unheated room, he takes her away and forces Iseya to write a statement for divorce. He carries Kie home to nurse her back to health, both actions which are viewed as very "improper" for an unmarried samurai. One night, Shimada comes to Katagiri with troubling news. Their friend Yaichiro Hazama was involved with some reformers inside the Shogunate in plotting a rebellion in Edo. The plot was discovered by Chief Retainer Hori of the Clan. The clan decided to deal with the rebels in secret. While some of the rebels were allowed to commit hari-kiri, Hazama was not so lucky. He was brought back to the clan's domain in a prisoner's cage and kept in solitary confinement. Katagiri and Hazama had both studied swordplay under Master Toda. Hazama left in anger when Master Toda chose to pass on the schools secret technique of the Hidden Blade to Katagiri instead of to him, even though he believed he was a better swordsman than Katagiri. Katagiri is questioned by the Chief Retainer about his connection with Hazama. When given a list of Master Toda's former disciples, and asked who amongst them is close with Hazama, Katagiri refuses to answer. He replies that, "A samurai does not inform on his fellows." Meanwhile, rumors are spreading about Katagiri and Kie. Though they clearly love each other, they cannot marry because they are from different castes. Katagiri takes Kie on a trip to the seashore, which Kie has never seen before. There, he tells Kie that she must return to her parents, now that she is healthy. He urges her to marry again. Kie refuses, saying that she has learned her lesson. She says that all she wants is to stay by his side and take care of him, but he commands her to do so. Hazama breaks out of his cell and barricades himself inside a peasant's hut, holding the family hostage. He taunts the Chief Retainer to send in his foot soldiers, saying that he will kill them one by one until he has built a mountain of corpses. Hazama is widely feared as the Clan's best swordsman. The Chief Retainer summons Katagiri and orders him to kill Hazama. Katagiri goes to see Master Toda, who has renounced his rank of samurai in order to become a farmer. Toda shows him a move - take his eyes off his opponent and turn his back, and suddenly striking when the opponent attacks carelessly. Toda warns him that it is a dangerous move that may cost him his life. The night before the duel, Hazamas wife visits Katagiri and begs him to let Hazama escape. She offers herself to him in return. Katagiri tells her that it is impossible. A group of riflemen have been ordered to the farmhouse as well. Katagiri asks them to give him until sunset to deal with Hazama. Katagiri reasons with Hazama, asking him to commit hari-kiri to preserve his honor as a samurai and to spare his wife the shame of being the wife of a criminal. The riflemen move in to surround the house. Hazama draws against Katagiri, who dodges at first, but finally is forced to draw as well. Katagiri is cut on the arm but remains on the defensive. He defeats Hazama with the move Master Toda taught him. But before he can make the final strike, Hazama is shot and killed by the riflemen. Hazamas wife had visited the Chief Retainer Hori and offered herself to him if he would spare Hazama's life. The Chief Retainer agreed but deceived her, as he did not send word to Katagiri. He boasted of this when Katagiri questioned him. Katagiri accused him of committing a foul act. Hazama's wife commits hari-kiri upon realizing that she has been deceived. To avenge Hazama and his wife, Katagiri assassinates the Chief Retainer with a small blade hidden in the handle of his wakizashi (presumably, "the hidden blade" or "oni's claw" move). He is left feeling empty and disillusioned with the Clan. Katagiri resigns from his status as a samurai because he does not want to kill again. He leaves for the wilderness of Ezo island. He finds Kie at her parents' house and asks her to come with him, and to marry him; Kie accepts.