The human body is capable of all sorts of things to survive difficult situations. Cha Do-hyun is a third-generation business heir who developed dissociative identity disorder (previously known as multiple personality disorder) in the aftermath of several life-threatening traumatic events. He tries to regain control over his life with the help of Oh Ri-jin, a first-year psychiatric resident who helps him secretly. But Ri-jin’s twin brother, Oh Ri-on, is a writer who is determined to uncover the unscrupulous lives of the rich and starts following Do-hyun around. Can Do-hyun take control over his condition before one of his seven personalities takes control over him instead?