Conan, Kogorou, and Ran are investigating a strange string of murders and cross paths with Heiji and Kazuha, who are also investigating the same crimes. They learn that the murders are linked to Takeda Shingen and his chosen war strategy Fuurinkazan.

While out on a trip for their homework assignment, Conan and the Junior Detective league rescue a young girl being assaulted. She later comes to the detective agency to speak with Kogorou. They decide to investigate after learning that a treasure is involved. During their travel to Tsuwano, the young girl meets with her friend, who seems suspicious. While investigating, the girl, Haibara, and Mitsuhiko are abducted.