In the future, people use "Toys" that grants them superhuman abilities such as ESP and telekinesis. This has led to a boom in petty crime and the need to use Toys detectives to track down criminals and bring them to justice.
Opera Koyabashi agency functions as detectives, Milky Holmes, who have four girls happy and energetic. Four trainees, Sherlock Shellingford, Nero Yuzurizaki, Hercule Barton and Cordelia Glauca, have formed a unit by the name of Milky Holmes. Under the guidance of Opera Kobayashi, they seek to defeat Arsene and her band of thieves. Though they need to get along with each other first.