Behind the innocuous exterior she portrays, there lies a monstrous beast, a cold-hearted killer. Consumed by her dogmatic hatred, she was soon lured into the dark side, driven into insanity and austere madness. Bang Yonghee, a temping seductress, is the nation's most notorious murderess. A pious believer of hatred and distrust; to her, there is no one out there to save this pitiful woman from the misery and virulent pain she is already drowning herself in. Bang Yonghee is a killer; so far, nearly 350 men have disappeared; at most 40 bodies have been found disposed of, entirely mutilated and vehemently condemed by her murder weapons; and there is no trace of her whereabouts, neither are there any signs of evidence of who lays behind these grotesque works. The numbers are climbing, raising above, and bringing terror to all the citizens of Korea. Bang Yonghee.. must be stopped.

And thus, Bang Yongguk; behind his cold-hearted, woeful character, there lies a Platonic romantic who cares and cherishes those near his heart. Ever since childhood, had he cared for Yonghee; ever since childhood, had he loved her like an elder brother should have. How she turned out to be the way she did blew his mind and was so obscure. Graduating at the top of his class from both highschool and university, unlike his younger, who had dropped out of her second year of highschool, he carried on with his life, leading himself to bigger and better opportunities. And most ironically, Yongguk became the chief leader of his department at Seoul's Police Department of Corrections; but with the knowledge of his sister's whereabouts, his life and career is on the line. And Yongguk is no more the leader his peers had respected.. Yongguk is an accomplice to the world's most heinous criminal since the Zodiac Killer.

A cop; typical, wallflower-like cop under Yongguk's wing.  A taciturn man, Jung Daehyun is; very prosaic, and almost banal. Daehyun was your typical high school student before moving onto university and graduating in the top five percent of his class. An overachiever, yes. Not too lanky, not too bulky; not too geeky, not too jocky. Rookie cop Daehyun enters the police department as a newcoming prosecutor, only to be met with one of the most thrilling cases he's ever come to study -- so heinous, so vulgar, so scornful -- he hasn't even seen cases like this being portrayed on TV. What he doesn't expect, though, is to find that the killer - once located and brought into custody - is a woman -- a very enticing, arousing woman. Ambiguous, is she, but her appealing visage must not distract Daehyun; not on his first case, not ever. A cop like him.. must not fall for a monster.