Shin Ha-Ru (Jung Yong-Hwa) works as a neuroscientist. He comes from a family that has had doctors for 3 generations and he is wealthy from inherited property. Shin Ha-Ru is a confident person who acts and speaks according to his convictions, but he has no mercy for people he views as scum. Geum Myung-Se (Cha Tae-Hyun) works as a detective. He acts and speaks surly around people, which causes people unfamiliar with him to assume he might be a corrupt cop. In reality, Geum Myung-Se is a kind and righteous detective. He was also once married to Kim Mo-Ran (Ye Ji-Won). She has a particularly strong libido. Shin Ha-Ru and Geum Myung-Se solve criminal cases together with help of Hypnotic Investigator Seol So-Jung (Kwak Sun-Young).