After losing her memory in an accident, a bullied high school orphan finds herself in the place of an identical-looking girl who's gone missing.

Prosecutor Cha Woo Jin lost his first love, Kim Seung Hee 15 years ago. He then meets a high school girl, Jo Eun Bi, who looks like his first love. Their meeting unleashed secrets and chain of events between Cha Woo Jin, Seung Hee, Jo Eun Bi, and the criminal.

Cha Dohyeon is a rich heir to a family company with one major problem. Due to suppressed childhood trauma, he suffers from dissociative identity disorder manifested in seven unique personalities who are out of his control. In order to overcome this disorder in secret, he hires a first-year medical resident to help him heal by killing off each personality one by one.