Elementary school teacher Natsuko is struck while working at school and pushed off the stairs in front of the park. Conan and his companions question Sugamoto, another teacher who had planned to walk her home, and parents Ueno and Kandachi, who had appointments to meet with Natsuko. Conan notices something strange while listening to their stories. Later, the police review a photo of the answer sheets Natsuko was grading. Jodie and Camel fail to discover any information that could help them solve the crime from the photo, but Amuro and Conan realize who the culprit is after seeing the picture.