Kasumi no Ayanosuke, a kunoichi and lone survivor of her village’s annihilation by a three-headed demon under Oda Nobunaga’s command, carries the weight of her brother Shinosuke’s final act: entrusting her with a mystical kodachi, one of three prophesied weapons capable of overthrowing Nobunaga. Adopting the masculine alias "Ayanosuke" to veil her identity, she embarks on a vengeful quest that slowly fractures into a conflict between clinging to life and confronting an unspoken longing for death.

Forging an alliance with Sakon Hayate and Ryoma Kogure—fellow survivors of decimated ninja clans—she seeks to unite the sacred blades. Bonds form amid turmoil: Kikyo Kogure, Ryoma’s sister, sacrifices herself to protect Ayanosuke, while Sakon’s hardened pragmatism clashes with her unyielding drive. A pivotal breach in her armor comes when Sakon uses her birth name, "Ayame," exposing her fractured identity and the tension between vengeance and selfhood.

In the climactic clash against Nobunaga and Ranmaru Mori, Sakon and Ryoma fall, leaving Ayanosuke alone to face the aftermath. Surviving where others perish, she shoulders their losses but refuses surrender, her resolve shifting from blood-debt to a defiance of despair. The enchanted kodachi, once a conduit for rage, becomes her instrument to disrupt cycles of violence. Her journey traces a path from grief-stricken fury to tenuous resilience, choosing endurance over oblivion as she redefines purpose beyond survival or sacrifice.