Lady Tiararose Lapis Clementille and Crown Prince Hartknights Lapis-Lazuli Lacmouth have been engaged since childhood. However, a day before their graduation from the kingdom's academy, Tiararose spots her fiancé embracing another woman, and, overcome with hurt, she recalls her past life as an avid player of an otome game called The Ring of Lapis Lazuli. In the game, Tiararose was no heroine—she was the wicked villainess who stood in the way of the prince and his true love, Akari.

Tiararose is destined to face condemnation at the graduation party, and she prepares to accept her fate. Hartknights accuses Tiararose of mistreating Akari, calls off their engagement, and banishes Tiararose from the kingdom. However, having witnessed Hartknights' contemptible behavior, Aquasteed Marineforest, the prince of a neighboring kingdom, steps in and proposes to Tiararose!

But Akari is not done meddling in Tiararose's affairs. Within her, Akari holds the power of Holy Prayer, a highly coveted magical ability that could undo the so-called villainess' happy ending.