Armed with his memories, Muichiro feels powerful and invincible, convinced that the demonic fifth moon has no chance against him.

The Hashira, Sanemi and Iguro, along with their comrades head to an abandoned castle on top of a mountain for a mission, while Tanjiro is being treated at the Butterfly Mansion for the wounds he suffered at the Swordsmith Village. Later on, the Hashira gather at the Ubuyashiki Mansion to hold a Hashira meeting, where Muichiro reveals how the marks manifested. In an effort to strengthen the entire Demon Slayer Corps from the bottom up, the Hashira Training begins...