Tantei Opera Milky Holmes (探偵オペラ ミルキィホームズ?) is a media franchise owned by the Japanese trading card game company Bushiroad. It consists of an internet radio drama, released in December 2009; a visual novel PlayStation Portable game, released in Japan on December 16, 2010; an anime adaptation by J.C.Staff, which begins airing on October 7, 2010; a manga adaptation serialized in Comp Ace from 2010; a trading card game tie-in with Bushiroad's Weiß Schwarz; and a series of novels.
The series is a homage to the detective fiction genre, and the four female leads are named after famous fictional detectives: Sherlock Holmes, Nero Wolfe, Hercule Poirot and Cordelia Gray.
Set in a futuristic world, there exist "Toys" which grant people superhuman abilities. This is responsible for a wave of crimes and necessitates employing Toy-using detectives to help solve them. Opera Kobayashi runs a detective agency, Milky Holmes, staffed by four aspiring young girl detectives who attend the Holmes Detective Academy, and each girl possesses their own unique Toy.