An explosive attack at Nichiuri Television during fall. The Satsuki Cup, which decides Japan's Hyakunin Isshu champion, is being recorded inside the studio. The crowd watches helplessly as flames consume the set. The blast creates a huge uproar and, as the building turns to embers, only Heiji and Kazuha remain inside. They are saved in the nick of time by Conan, who hurries to the scene. The bomber's identity remains unknown. No clues point to the perpetrator's motives or affiliations. The scene remains under investigation.
Amid the chaos, Conan encounters a striking enigmatic woman who claims to be "Heiji"s fiancée." Her name is Momiji Ooka, the Kyoto High School Karuta champion. Coincidentally, Kazuha is set to compete against Momiji in the Hyakunin Isshu, so she starts training with help from Heiji"s mother Shizuka, a seasoned Karuta player.
Simultaneously, in a Kyoto suburb house near Arashiyama, the current Satsuki Cup victor is slain. Photographs of the scene show scattered cards, hinting at a deeper plot. The crime scene shows scattered cards, hinting at a deeper plot. The victim"s body is surrounded by numerous Karuta cards.
Conan, Heiji, and officers from Osaka and Kyoto police launch an inquiry into the Satsuki Cup and the linked homicide. As they probe, they uncover a hidden secret tied to the Hyakunin Isshu.
