The marquess' eldest daughter, Rose Adeel, admires her fiancé, the third prince, Licht, and has worked hard to become a suitable princess for him, but she witnesses the moment Licht falls in love with another girl. While Rose is deeply hurt, she realizes that her current position is exactly that of a fashionable "villainous noble girl."

"The only thing I can do to support Licht-sama, whom I love so much, is to stand in his way as a villainess and ignite their love...?!"

It was Licht's older brother, Richard, who reached out to her...! Will Rose be able to become "the greatest villainess ever"?!