On the day before her downfall, Lady Tiararose Lapis Clementille recalls that she is in an otome game that she had once played in her former life. She used to adore the main love interest Prince Hartknights Lapis-Lazuli Lactomuth, but unfortunately, she was not reincarnated as the heroine, but rather as is his worst enemy—the villainess fiancée.

At their graduation ceremony, without blinking an eye, Hartknights condemns Tiararose for alleged crimes, breaks off his engagement, and proclaims the heroine Akari as his new bride-to-be. No matter whether Tiararose is innocent, he banishes her from the kingdom. But before her sentence can be carried out, a shocking figure appears. Aquasteed Marineforest, the prince of a powerful neighboring country, has been harboring feelings for Tiararose for quite some time, and announces his intention to marry her!