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 poison is found on her glove. Conan tranquilizes her and reveals the culprit to be the captain of the tennis team, Fumihiro Azuma. Conan explains Azuma high-fived Goutou with a poisoned glove and poisoned his hand; thus explaining why poison was found from Goutou's drink, towel, and Sonoko's glove. As a result, Goutou ingested the poison when he licked his fingers while changing the grip to his racquet. As evidence, Azuma's glove was found hidden in a tennis ball and poison was confirmed to be on it. Azuma confesses explaining Goutou injured him purposely to usurp his position in the competition and consequently made him lose his sponsors and scholarship.
