After a devastating assault by the Masked Demons, the Shinsengumi's Eighth Division is decimated, leaving Heisuke Toudou as the lone survivor, gravely wounded. Tasked by the local lord to revitalize the Shinsengumi, Toudou enlists eight criminals to fill the roles of the fallen captains. As they strive to redeem themselves, one rebel meets a swift end at the hands of a former assassin. Toudou struggles to mold these reformed convicts into a cohesive unit, especially with the fiery Ichibanboshi, driven by a tragic past, challenging his leadership. Amidst the chaos, Toudou vows to defend the shogunate against internal and foreign threats, while rival factions like Kogorou Katsura's group maneuver to seize power in the waning days of the Edo era.