Wanting to become stronger herself, Rin received training from Manji, but is still a long way off from matching him in ability, much less the Ittou-ryu. Rin, in her melancholy, is drawn in by a sound, and finds a man training on his own. 'Some day I'll be like him', Rin tells herself, then is astonished upon seeing the man's face. It's her arch-nemesis, the head of the Ittou-ryu, Kagehisa Anotsu.

Rin, who has come to see the festival, meets a cheeky little kid, Renzou. At the mask shop, things get dangerous between Manji and Araya, until Araya's son Renzou shows up and the hostility dissolves. Araya and Renzou then leave. Having watched Manji from behind, for some reason Rin continues glaring at Araya with eyes full of shock and hatred.

Manji and Rin involve the four known as Mugai-ryu, who hold information on Kagehisa, in order to assassinate him. Lying in wait on the road that leads out of Edo, based on information only known to Rin, she and Shira close in on Kagehisa as he tries to flee from the others.

Manji wants to go after Rin, but he has no pass. That's when Souri and Magatsu appear before him. Souri tells Manji that he can acquire as many passes as Manji likes, but there's a condition. Meanwhile, a gray-haired, one-armed Shira appears before Hyakurin and Shinriji as they re-work their plan for assassinating Kagehisa.

Habaki's scheme gets Manji trapped in a dungeon. Habaki uses a doctor, Burando Ayame, to try and solve the mystery of the immortality. For the sake of the advancement of medicine, Burando sinks a scalpel into Manji's body. Meanwhile, while waiting for Manji's return, Rin is caught up in a strange cohabitation with Doua and Isaku, who had been searching for a place to stay.

Burando succeeds in transplanting Manji's left arm onto the test body of Dewanosuke. From that starting point, more tests succeed. But Habaki puts pressure on Burando, and demands results. Habaki's blade closes in on the imperfectly immortalized Dewanosuke. Rin meets with Doua and Isaku in the street as she searches for Manji. That's when the official that Doua knocked over appreaches them.

Ever since the Dewanosuke incident, Burando kept making blunders. He is finally thrown in solitary confinement by Habaki, and goes insane. But as a result of his madness, Burando grasps something important about the immortality experiments: That humans are essentially otters. Meanwhile, Rin and Doua resolve to infiltrate Edo Castle to rescue the surrounded Manji and Isaku.

Manji and Rin finally reunite. But the formidable foe they made in Habaki in the dungeon blocks their escape. Then Doua and the presumed dead Isaku arrive as backup. The dungeon begins to cave in. As their escape nears, an unexpected person appears before Rin and Manji. Then, the answer that Burando arrived at from the results of his experiments...

Rin and Manji chase after Kagehisa, but Shira attacks them and Rin is taken away. Manji goes to rescue her, and meets not only Shinra, but Renzou as well. Manji fights Shinra in order to rescue Rin. But astoundingly, what slashes at Manji is Shira's left arm, which should have been lost.

Manji is wounded from his duel with Shinra. Renzou picks up a sword and tries to kill Manji, but Rin and the others talk him down. Meanwhile, Habaki is livid upon learning of the attack on Edo Castle. Habaki wants to pursue Ittou-ryu, even in absence of its leader. As a result, one of the Ittou-ryu enters a mountain village. Habaki's daughter, Ryou, tries to subdue him to be of use to her father.

The Ittou-ryu, Rokki-dan, and Manji and Rin all gather in Nakaminato, as if guided there. They all bear their motives on their swords in the moment they begin their final deathmatch. Deceive, subdue, and dance in chaos. Sparks will fly in the decisive batte between the strongest. The last laugh belongs to...