During autumn, a bombing incident occurs at Nichiuri TV while the Satsuki Cup is being filmed inside. Heiji and Kazuha are the only ones left inside as the building burns, but are rescued by Conan just in time. The bomber's identity and motives remain unknown. Amidst the chaos, Conan meets a stunning young woman who claims to be Heiji's betrothed, Momiji Ooka, the Karuta champion at Kyoto High School. Kazuha is set to compete against Momiji in the Hyakunin Isshu and trains with Heiji's mother, Shizuka, who is adept at Karuta. Simultaneously, the reigning Satsuki Cup champion is killed in a Kyoto home, and Momiji is pictured at the crime scene. Karuta cards are also found around the victim. Conan, Heiji, and the police in Osaka and Kyoto initiate their inquiry into the Satsuki Cup and the related murder. As they delve further, they discover a secretive association with the Hyakunin Isshu.