A family doctor working for a powerful corporate household discovers that the man she has feelings for has a dangerous secret: his personality changes completely at night, as if he becomes a different person.

By day, he appears cold, controlled, and distant, but at night he becomes intense, possessive, and emotionally volatile—insisting she stay close to him and not trust the daytime version of himself.

Caught between two opposing versions of the same man, she is forced into a confusing and emotionally unstable relationship where she can never be sure which “him” she is dealing with. As both sides grow increasingly fixated on her, she slowly becomes entangled in a secret she never intended to uncover—and a man she can no longer easily escape.