Satoshi Oosawa

Serial murders involving all kinds have happened. All the victims are from a Music School led by a famous pianist. Conan and company have been invited to a opening concert of the Music Hall built by the pianist. The biggest attraction of this concert is the world famous violin called "Stradivarius" and a special appearance of a singer who has perfect pitch.

The characters receive an email from Ovan requesting them to go to Δ Hidden Forbidden Festival where a mysterious summer festival is set up. There they encounter an AIDA Chim Chim who wishes to peacefully co-exist with the players of The World. It then transforms into the word "Returner", which Haseo assumes it to mean that Ovan will return to The World.