After a traumatic experience in his childhood, Cha Do Hyeon, a third-generation billionaire, suffers memory lapses and his personality then scattered into seven different identities. Wanting to regain control over his life he asks Oh Ri Jin, a first-year psychiatric resident, to try to helps him secretly, but she eventually falls in love with one of his personalities. Meanwhile, Ri Jin’s twin brother, Oh Ri On, is a famous mystery novelist who investigates about Do Hyeon and his family.