Mizuki Gekkou, a girl who was born an unlucky orphan, born in the 21st century. She was transported back to a mysterious world of the past, Mystic Kingdom, through a car accident. She finds herself trapped in the body of one of her previous incarnations: Kanzaki Mizuki, the smallest daughter of King Kanzaki. In her new timeline, she has four brothers and three sisters, as a princess, she lost her power for defending her kingdom. In order to find her power back, she leaves her kingdom to Mount Mystic, a sect that trains their disciples into becoming immortals. With the help of Kaito Domoto, she passes through various trials to become his only disciple. As the two spend more time together, Mizuki falls in love with her teacher but doesn't reveal her true feelings until the end. Eventually, the truth is revealed that she was born as Nuwa descendant and has access to godly power. But her mortal body was too weak to control the godly power. Therefore, she lost her power. In order to get her power back, she has to collect the five godly weapons and absorb their power. But she accidentally summons the demon god. The Demon God transfers all his power into her body afterward, and Mizuki falls into the world of Emptiness. She unleashes the Great Desolate Energy Force to become the new ruler of the Demons. Kaito tries to get her to return to the righteous path and comes to her side alone to accompany her. When Mizuki realizes Kaito's true feelings for her, she decided to let herself be killed by him to restore peace to the world. But Kaito doesn't want to kill her. In the end, Kaito decides that the best he could do is seal her inside the Nine Ghostly Tower.