In a fantasy world where the Church of Light and the Church of Darkness have waged a thousand-year war, the Church of Light is on the verge of defeat. Desperate, they succeed in summoning the fabled Hero of Light, a young woman named Anastasia. But their hope is immediately shattered by a prophecy: Anastasia will be killed in exactly nine days. The one destined to slay her, according to the prophecy, is the very priestess who must accompany her—the earnest and devoted Priestess Maiden of the Church of Light.

Anastasia herself is initially an emotionless, almost mechanical warrior, having been summoned as a weapon rather than a person. The Priestess, charged with supporting her, finds herself torn between her duty to the Church and her growing attachment to the hero. Over the course of the nine days, the two must fight against the relentless forces of the Church of Darkness, whose thirteen leaders wield bizarre and terrifying supernatural powers. Each enemy requires the hero to understand the nature of their ability before she can overcome it, turning every battle into a puzzle as much as a clash of strength.

As the countdown advances, the bond between Anastasia and the Priestess deepens, and Anastasia gradually begins to develop genuine emotions and a will of her own. But the weight of the prophecy hangs over every moment. The Priestess learns that she is the prophesied murderer, a truth that forces both of them to confront whether destiny can be defied. Their journey takes them through devastating losses—including the death of a beloved knight—and a climactic confrontation with the time-manipulating White-Faced Archbishop, who captures the Priestess to force the prophecy’s fulfillment.

In the final volume, Anastasia must rescue the Priestess and choose whether to accept or reject the fate foretold. The story culminates in a dark, tragic, yet hopeful resolution where the two protagonists reject blind submission to destiny and forge their own path, even if the cost is immense.