Kaiketsu! Suzunari Gakuen Tantei-bu

A high school detective club at Suzunari is made up of three male students—Suzaku Tachibana, Kouhei Hiba, and Soutaro Tsubaki—and a cat named Boo-chan. The club has remained all-male because Boo-chan has not yet approved any female members. Suzaku identifies Aoi Kaidou as a potential candidate, and Boo-chan accepts her, though she is described as strange and rarely smiles. The story follows the four students and the cat as they investigate various incidents at their school.