Kenshin, Sanosuke, and Yahiko scramble to take back Megumi from the Kanryu residence. They are confronted by Han'nya, a spy of the Oniwaban Group. He trifles Kenshin with his martial arts skills and his "Arm-extension Spell", but Kenshin successfully conquers him when he uncovers the secret of the technique during the fight. Just when it looked like the battle was up, Han'nya removes his mask and reveals his startling true face.

At last, Kenshin faces off against Aoshi Shinomori, the head of the Oniwaban Group. In the Bakumatsu Era, the battle-obsessed "Oniwaban group" lost their meaning of existence after surrendering the castle they served without even being able to fight. Aoshi is unable to bear this regret and is in earnest pursuit of the title of the strongest warrior. As a former Revolutionary warrior, Kenshin cannot tolerate conflict without morality. Two men who made killing their profession in the Bakumatsu Era clash against one another, putting their pride on the line.

In order to kill Kenshin, Kanryu uses his Gatling gun and rains a flurry of bullets at him, uncaring that the Oniwaban Group that was under his command would also be hit by this attack. In the face of this evil act, the Oniwaban Group make full use of their individual abilities to counter the Gatling gun. At this moment, theirs and Kenshin's purpose become one. Kenshin and the Oniwaban group team up to challenge the overwhelming power of a modern weapon.