A neuroscientist Shin Ha-ru with a special brain, a selfless detective Geum Myeong-se with a kind brain, a law hypnosis investigator Seol So-jeong with a timid brain, and Kim Mo-ran with a hyper-sexuality brain, will join the force and investigate criminal cases as a team. A neuroscience team has been established in order to deal with the increasing number of crimes related to brain disease, and Ha-ru joins them as a consultant. Coincidently, Myeong-se and Ha-ru get involved in an ill-fated relationship, and brutal cooperation begins. What will happen during the all-too-human investigation full of madness and plot twists?