In a barn, there’s an ill girl who is periodically fed by the stable boy, condemned to be there by the lord and lady. One day, the saint of war visits her and says she is needed for the kingdom. She then heads outside to greet the prince, but before she goes, the lady comes out and insults her, saying that she’s a devil and not the girl he’s looking for. The prince accepts her nonetheless and takes her away on his horse. The stable boy, running after them, is eventually anointed to be her squire.

The girl is trained for seven years to be a perfect warrior. One day, on the battlefield, she nearly dies, but the saint of war comes in time to tell her how she can survive and win. She follows her orders, emerges victorious, and presents the head of the prince’s enemy to him. The squire spends the rest of the day rinsing blood from her.

When the girl turns twenty, she has already been visited by the saint of war seven times, each visitation allowing her secrets in battle that make her victorious. Together, they wreak havoc on the prince’s enemies and spare no one. However, one day, in battle, a knight impales her thigh right before she manages to kill her, which forces her into recovery. The squire, taking care of her, slightly resents the prince for making her risk life and limb for him. However, the girl is still convinced of the prince’s love for her.

Eventually, the prince’s kingdom grows and grows from the girl’s victories. He becomes king. The girl is celebrated as a legend. However, she is tormented by her conquests in her dreams, which are violent and bloody. She is unsure which are dreams of battles of the past versus dreams of battles of the future. One day, she is tasked to invade the Gray City, which she does even though the squire chastises her for blindly following the prince’s mandate. She continues anyway, but on the outskirts of the Gray City, she hesitates in fighting a boy with an axe, nearly perishing. On the brink of death, she feels relief.

The girl wakes up in a courtyard with a fountain. Accompanied by a priest, the king tells her to rise and look into the fountain. She sees herself in her younger age in its reflection. The king says that the fountain is how one can peer into their own past and future but also, per the priest, a means by which the present can pass words through time as well. He then tells the girl to speak into the fountain, which she does. She realizes that she is the girl, the devil, and the saint of war, all in one. For the rest of that day, the girl tells her past self how to arrive at victory in all of her conquests, including that of the Gray City. The king says that she must always fight for her.

With the saint of war, the girl does it all again. She meets the saint of war in her barn, grows to become a perfect warrior, and earns victories on the battlefield with the saint of war’s help. Still, the squire resents the king all the same, but the girl remains committed to him. This time, she vanquishes the Gray City, after which she is sent to the Kentish Isles where victory will turn her king into an emperor, which she does. On the day of the invasion of Kemet, her next conquest, the squire tells her she cannot win against her enemy, but she pushes on anyway. She is struck by an arrow in battle, after which she is taken back to the fountain to do it all again.

In her next life, the girl makes it to Kemet. In the life after that, she gets into Kemet’s palace. In the life after that life, she arrives to the palace’s throne. Still, however, she is struck by arrows. At the fountain, the squire is upset and has an outburst. The now-emperor and priest contemplate whether the girl has outlived her usefulness. The priest, however, insists that she keep fighting, for her next life will grant godhood to the emperor.

The saint of war, now angry in this life, sends the girl on her way once again. She takes victory after victory again. This time, she names her squire and finds him dear to her, meanwhile her love for her emperor wanes. Now, in battle, the saint of war is frustrated as she fights alongside the girl. One night, the girl dreams of killing her emperor. She falls in love with the squire, and affirms that she isn’t merely a weapon to be used, and makes love with him.

Before the girl is sent to take Kemet again, the squire tells her that she cannot win, that she should run away even if she’s a coward for it, that he would love her as a coward. Still, she goes out and kills Kemet’s queen once and for all with only minor bruises, but she eventually gets poisoned by her vipers. At the fountain, the now-god tells her to look into it once more, but she refuses. The god, seeing her challenge, then apprehends the squire and holds a blade to his neck, threatening her to look into the fountain.

In the fountain, the girl leads herself through battle after battle, up until the taking of Kemet. In the fountain and in reality, she looks back to her squire with love. Fulfilled by this, the squire twists his neck into the god’s blade and kills himself. The girl then kills everyone around her, including the god and his men. She holds her squire’s body in her arms. She wonders if she should start over again, but she knows only the same bloody history will ensue.

The girl sees that the priest is still alive. She lifts him into the air by his hair, asking him how it all began. She figures out that the priest is the one who first found out about the fountain’s secret, from which he lived countless lives until he became close to the prince. The priest says the fountain allowed him to turn from a nobody to a somebody, but the girl asks her if it was worth it. He threatens her, saying that if he dies, then her legendary history will end and no one will remember. She kills him, knowing that one person will remember her no matter what.