Segawa Rio, a quick-acting detective, gets transferred to the Tokyo Metropolitan Police's Violent Crimes Division after she got shot during her previous case. She is made to work together with Nagumo Jun, a level-headed but eccentric psychology professor whose skills at behavioral analysis are the key to tracking down the criminals. There's also Teranishi Kei, a shy young detective who's had a crush on Segawa since their days at the academy.
