The detective boys are hiking on a trip to find stag beetles on a mountain forest. Later Conan receives a phone call from Ran and Sonoko who tells "Shinichi" that a burglar tried to steal Sonoko's bag. Since it relates to a murder, Conan investigates a picture sent by Sonoko to learn about the dying message. While at it, he helps the Detective Boys solve one of Agasa's code.

While on set for a Detective show, one of the scriptwriters is murdered! The suspect is obvious, but there is a lack of clear proof.