Sonoko takes Ran and Conan with her to cheer for her senior tennis player, Takao Goutou. Goutou collapses in the middle of the match due to poisoning and is rushed to the hospital. The ones who are suspected to have poisoned him are one of the two girls he is dating, and Sonoko who becomes the prime suspect when the poison is found on her glove. Conan tranquilizes her and reveals the culprit to be the captain of the tennis team, Fumihiro Azuma.