Ichi Ichi, an goze blind woman who is traveling Japan to meet her mentor, the Zatoichi.
A travelling Samurai Toma Yamahira befriends her and informs her that he saved her from bandits. In fact, Ichi was the one who killed the bandits. They travel to a town run by the Shirakawa family, a Yakuza family that are plagued by the Banki-to, a group of mercenaries. The group is headed by Banki, an evil man who is skilled at sword fighting, however he has an unattractive face. Ichi is befriended by Kotaro the boy who lives with his drunk father.
They are then followed by five Bankito they are after Toma’s cash after Ichi helps Toma to get cash from Ch-han. Toma refuses to fight, and he is required to make use of his sword to defend himself. The gang is defeated by Ichi. The son of the Shirakawa leader, Toraji, arrives after the fight and assumes that it was Toma who slew the men and makes Toma his personal bodyguard. Ichi is convinced by Kotaro and his father to remain in the hope of the famed blind swordmaster, Zatoichi, passing through. Toma acknowledges that he is unable to draw his sword due to guilt over blinding his mother in an accident.
The Bankito are plotting their revenge. They take out the head of Shirakawa. Toma is unable defend herself and is rendered unconscious. Ichi acknowledges that it was she who killed the men before her and, after showing her skill, the second-in-command of the Bankito believes in her and leads her into the mountains to see their leader, Banki. She kills two Bankito who were skeptical of her skills and Banki is able to take on her, but she defeats her. Banki informs Ichi while he is wounded, that he has been her mentor. They had fought, however, Zatoichi would die during battle because of an aggressive disease. She is thrown into a locked ditch and then left to die. In the moment she loses consciousness, Ichi drops the bell she was handed by Zatoichi. Ichi HD
The backstory of Ichi is then revealed. She was born blind. When she was young, Zatoichi rescued her and put her with the group of goze who gave Ichi the small bell that she could keep him in mind by. Zatoichi came to her every time she got older, and secretly taught her the fighting techniques Zatoichi had learned. Ichi grew up to be a beautiful and musically gifted woman, and an accomplished sword-fighter. One of her patrons had raped her following one of the shows of her goze group. Goze were not allowed to marry and obliged to remain celibate, so she was later removed from the goze household however it broke the others’ hearts. She pleaded with the person who had raped and sexually assaulted her to speak to her in order to enable her be allowed to rejoin the group. He laughed at her and attempted to attack her once more. She was able to draw the sword that she concealed in her cane, and killed him. Ichi then traveled to Japan to search for Zatoichi, who she believed was her father. That was how she came across Toma.
Toma is targeted by people of the Yakuza clan for his deceit, but Toraji rebukes the attackers, stating that they still need Toma’s aid to defeat Bankito. Toma, Kotaro’s father who has been reformed, goes to the Bankito hideout along with Kotaro and saves Ichi. Banki was ruthless and swore revenge. While recovering, Ichi explained that she is looking for Zatoichi because she wanted to see him for the last time before she commits suicide. Toma manages to convince her to give up the idea. Toma is later able to leave her to assist the Shirakawa against the Bankito as she heals from her injuries. When Ichi wakes up Kotaro informs her of the battle that’s taking place within the town.
The Bankito outnumber the Shirakawa by 2 to 1. However, Toma is unable to take his sword. But when Banki demands Toma to step forward and fight him, Toma is willing. He is able to overcome his guilt and draws his sword. The two fight, and Toma shows the world that he’s an expert swordsman. Banki is also mortally wounded by Toma’s fatal strike. Toma dies in Ichi’s arms and tells her not to lose hope. When Toma dies Banki attempts to attack Ichi but she is able to stop him and eventually defeats the clan leader his horribly scarred face exposed. Believing that they are in danger, the few remaining members of the clan of Bankito flee.
In the next scene, we see Toraji rebuilding the city of his Yakuza clan, and taking over as its chief. Ichi sings Toma’s favourite song, and is seen together with Kotaro on his grave. As she plans to carry Toma’s katana to her mother’s grave, she bids her friend Kotaro goodbye and gives him an earring as a keepsake (the same one that Zatoichi had gifted her when she was younger). After saying that Kotaro was correct then she went on her way.