There is no doorbell in the detective agency, and you can only visit by knocking on the door. There are two young detectives who are both partners and rivals. There is a beautiful high school girl who cooks and cleans part-time, a policewoman who eats snacks all the time, and a mysterious person who appears regularly in the second-hand bookstore... A group of seemingly strange people, but they make it difficult for the cunning murderer to hide. Katamushi Hyoyu, who specializes in motive analysis, and Gotemba Daori, who focuses on studying the modus operandi, can solve even the most clueless cases with their perfect cooperation and tacit understanding!