Yoo Jin Kook is a veteran detective who is getting weary of his job. The only light in his life is his younger sister, Yoo Jin Kang. He dotes on her and is protective of her like a father figure ever since they lost their parents. When Jin Kook starts investigating a suicide of a university student, he can’t help but feel that the enigmatic Kim Moo Young, may have been responsible for her death. Moo Young seems like a nice guy who works at a Korean beer microbrewery, but there seems to be a dark side to him. When Moo Young meets Jin Kang and the two begin to develop a relationship, Jin Kook is determined to stop it. But can Jin Kook protect Jin Kang when she needs it the most?