Reincarnated after a car accident 17 years ago, Adelaide Chamille Borbon's second life could not be more ordinary. As a nobleman's daughter residing in the countryside, she yearns for excitement before being married off. When Adelaide overhears the news about a black-haired woman coming from another dimension, she does not hesitate to rush to the capital and meet this mysterious "saint" at the debutante ball.

Elsewhere, Felix Mikhail Noah Elias is fed up with the rumors surrounding him and the so-called saint. In reality, the latter is a wolf in sheep's clothing—she relentlessly tries to seduce him and spreads false rumors for her own benefit. To free himself of the unwanted guest and the bad reputation she brings him, Felix has no choice but to find an aristocratic lady and arrange engagement as soon as possible.

When their lives intertwine, Felix asks Adelaide to temporarily act as his fiancée. But although he assures her that no feelings will be involved, with Adelaide constantly by his side, Felix may find it difficult to stay true to his simple promise.