Kwon Jisu had been demoted to a local cop from her high position as a detective. She had made a mistake as a detective and as her punishment, she was demoted. She would rather get fired than become a local cop but with persuasion from the senior detective, she decided to take his advice. 
During a police check, she meets a kind of man she detests. Too bad that man is someone she cannot get away from and too bad she is the one in charge of him. It's too bad she starts to fall for him and it's too bad he gets involved in her mess.

Kim Soohyun, the billionaire with a split personality

Yoon Shi Yoon, the happy police officer

Kai, the overprotective cousin