The Detective Boys, including Conan, accompanied by their teacher Miss Kobayashi, visit the Rampo residence. The storehouse which Rampo used as library entailed a great deal of valuable books, stimulating the excitement of Conan and the rest. In the meantime, Detective Sato and Detective Takagi arrive, whereupon they are informed that a murder case has taken place in a nearby park. And - which is more - the victim's belongings seem to be related to the storehouse that was often closed to the public... The modern-day Detective Boys shall challenge this difficult case!