The son of a world famous mystery writer, Jimmy Kudo, has achieved his own notoriety by assisting the local police as a student detective. He has always been able to solve the most difficult of criminal cases using his wits and power of reason.
Genki Ishikawa, a taxi driver who calls himself a "Kogoro Mori geek," comes to the detective agency. At the "Jewelry Washing Festival", Ishikawa spots a suspicious duo taking candid photos of the participants' cars. The diamond ring was not stolen and Ishikawa has disappeared. What is the purpose of the suspicious duo?