Sakon Shiba, Tetsuro Tamba, a wandering ronin, rides into a mill where three peasants—Yohachi, Gosaku, and Jinbei—have seized the magistrate’s daughter, Aya, as a bargaining chip. The magistrate’s soldiers ride to negotiate, offering clemency in exchange for Aya’s return, but the peasants refuse, insisting that the hostage will be freed only if the regional lord agrees to lower taxes for the starving villagers. A failed sneak attack by the soldiers leads nowhere, and the lord quickly assembles a new party, including his samurai Kikyo, Mikijiro Hira, and the vagabond samurai Kyôjûrô Sakura, Isamu Nagato, to break the stalemate.
When Shiba encounters the fresh entourage, he persuades Isamu Nagato to switch sides, drawn by his sympathy for the peasants’ plight. After a second rescue ends in disappointment, the magistrate escalates the crisis by hiring mercenaries and taking Gosaku’s daughter, Yasu, as a new hostage. Confronted with Yasu’s capture, the peasants and the mercenaries strike a grim pact: Aya will be freed and the peasants will be left unharmed, provided Shiba endures 100 blows as punishment. They all swear to honor the bargain.
Shiba is taken into custody and whipped, while Aya watches in horror and pleads for mercy on her father’s behalf. Yet the beating continues, and Shiba vows revenge on the magistrate for breaking the samurai code of honor. In retaliation, the magistrate orders the killings of Yohachi, Gosaku, and Jinbei, though Jinbei manages to cast a signed petition for the regional lord into a river before his murder.
Sakura slips into the magistrate’s house and tells a serving girl of the peasants’ killings. Alarmed by the magistrate’s treachery, she frees Shiba and is soon slain by a dungeon guard. Moved by Shiba’s integrity, Kikyo decides to abandon his current allegiance and joins the other outlaws at the mill, aided by Sakura’s earlier defection.
A crucial turn arrives when Sakura, visiting a love interest, Oine, learns she is being held at knifepoint by the magistrate’s men. He reveals the petition’s location—the mill—and is released in exchange for her freedom. Ouchi Genma, the land’s greatest swordsman, arrives with a large force to assault the mill once more; Shiba and Kikyo hold the line as Sakura arrives in the heat of the battle. Shiba defeats Ouchi and then races to persuade a wary group of peasants to deliver the petition to the lord, but they balk. Enraged, Shiba turns his fury toward the magistrate, only to be checked when Aya steps forward and begs for mercy, throwing herself between Shiba and her father. The magistrate tries to flee, but Shiba cuts off his hair bun and declares that the lord and the peasants must “see his disgrace.” With the magistrate exposed, Shiba returns to his companions, and the trio accepts an uncertain, open-ended destiny as they walk away in a direction chosen at random.
