Detective Mun is a South Korean detective who is sent to investigate after Sun's escape from prison.
Detective Mun is earnest and does what he can to help Sun, but is often evaded (much to his dismay).
Some time ago, Mun trained and fought in the same martial arts tournament as Sun, soon getting the chance to fight her. Though cocky, he was defeated by her and since that day, he has hoped to someday face her again.
Season Two Edit
Receiving a report of possible runaways in Mrs. Cho's apartment, Detective Mun and his partner pay her a visit during a rainy afternoon. He is greeted with an old lady facade that he quickly dismisses when he shows the prison uniforms. Mrs. Cho allows him and his partner to search the premises. When he hears a thud in a nearby room, he rushes inside to find his partner unconscious and Min-Jung visibly frightened in a corner with her hands in the air.
A glimpse of Sun Bak running away and Detective Mun dashes behind her; they climb several flights of stairs and find her on the rooftop. Mun fires a warning shot while shouting to stop. Edging closer to her, he holsters his sidearm and pulls out his handcuffs, but Sun fights back the moment his hand grips her arm. They have a brief manual combat. As Sun pins him to the ground, Mun remembers her from the tournament and is knocked unconscious in the rain.
Detective Mun decides to visit Sun's trainer. He shares some tea and asks if he has seen Sun Bak or know where she could have gone. Mun, then, asks if he believes what the news has said about Sun, agreeing that he himself does not buy into the rheortic that she was mentally unstable and truly behind the killings of the three (fake) guards at the prison. They reminisce on her skills in martial arts; Mun gives her trainer his card, telling him that Sun cannot do whatever she plans to do alone, only coming by as a friend. He thanks her trainer for the tea and leave his home.
Another morning of cleaning the cemetery, Mun encounters Sun, sitting by the graves of her mother and father. He passes condolences for her father's passing, while she corrects that he was murdered. He reassures her that he does not want to stir any trouble or tention between the two and only wishes to help and protect her. Though she debuffs the need for protection, Mun tells her that he and a few of his co-workers knows her brother is doing or has done something criminal but have yet to prove it. Sun questions the how flawed the law is.
Mun challenges Sun to a fight, a rematch. The terms were that if she wins, she is given freedom to do and go as she wishes without his interference; if, however, he wins, she has to submit her own testimony against her brother under his protection. They duel in the cemetery, complimenting Sun on her fighting and sharing a bit of memory about how his teacher tells him he fights with his head rather than his heart. Mun makes a comment that when Sun fights, she does not fight the person but the feelings within her, though Sun does not give him an answer.
Admist the fight, they share a brief, sweaty kiss before Sun knocks him to the ground and leaves.
Detective Mun emerges from the crowds at Joong-Ki's gala. With an arrest warrent, Mun tells him that things will run smoothly if he complies know and does not resist arrest. Within a second, Joong-Ki pulls a small pistol from his pocket and fires a shot into Mun's abdomen.
It is later on revealed in a televised news report that Mun is hospitalized but will make a nice recovery.