Conan, Ran, and Kogoro are invited to visit Shimonoseki by the lawyer Oi, who they previously met during the inheritance dispute case. The clients are the fourth generation owner Izumiya Makoto and his daughter Kaede, who run the long-established fugu restaurant Izumiya. A thief entered their house while the restaurant was busiest and no one was home and stole their family's treasured cooking pot. While the pot is valuable, to the family, its true worth is in the broth that's seeped into the pot since the restaurant's founding. Conan and his companions question the four suspects identified by Oi's investigation, but...
