In modern society, humans and beastkin live together. Under the government's strict management, beastkin utilized their extraordinary physical abilities and senses to work in highly specialized professions, becoming cogs in the machinery of society. However, there were also those who fell out of that machinery and turned against society. Standing on the front lines against them is the Metropolitan Police Department's Special Case Response Unit, the "Special Unit." There, "beastkin detectives" with extraordinary intuition and "human detectives" who tame them and sometimes act as their brakes form buddy pairs to take on various special crimes. ──The Special Unit's office here has a strict atmosphere... or so you'd think. On the floor are rope toys, a scratching post, a tattered sofa with a fur-covered blanket, and a cat tower that no one knows who put there.