Woo Tae Suk is a seasoned and well-known investigator with a long professional history, but despite this, he is a lonely and bitter guy. It all stems from his sole emphasis on solving crimes, despite the fact that his activities are highly contentious because they straddle the boundary between good and evil. Woo Tae Suk meets a psychopath, but he is unable to arrest her due to a lack of evidence. The woman eventually agrees to assist Woo Tae Suk in solving additional instances.