Ron Kamonohashi, once celebrated as a prodigy at a prestigious detective academy, faces a fall from grace after a critical blunder leads to his expulsion and a ban from detective work. Years later, he is approached by police officer Totomaru Isshiki, desperate for assistance on a serial murder investigation. Discovering Ron's disheveled, reclusive lifestyle, Totomaru convinces him to lend his expertise. Thus begins the unlikely partnership of these two, as they tackle their first case together, blending Ron’s sharp intellect with Totomaru’s determination in a thrilling quest for justice.