A large group of reporters have gathered in front of the Kudo family home. Everyone online is talking about how Shinichi solved the Fighting Red Tengu murder case. Conan decides to hide in Agasa's home until the commotion blows over. Haibara, Genta, Ayumi, and Mitsuhiko are asked by their homeroom teacher Kobayashi to visit Higashio Maria's home after school. Maria should have been at school that day, but she never showed up. Believing Maria most likely went to look for the treasure hidden by her late grandmother, Haibara and friends begin deciphering the treasure hunt clues, but...

Kogoro is invited by a female fan named Toyoko to visit her monja restaurant with Conan. Kogoro is shocked to discover that Toyoko is an old woman who looks nothing like her photo. While eating monja, Toyoko chokes and spits out a cabbage core. She claims someone put the core in the monja in an attempt to take her life. Toyoko suspects the culprit is one of her three childhood friends Eiko, Kyoko, or Yuko. Kogoro is hired to talked to the three women, and all three of them seem to resent Toyoko..