During a chaotic bombing incident at Nichiuri TV, Conan rescues his friends Heiji and Kazuha. Amidst the confusion, a mysterious girl named Momiji Ooka emerges, claiming to be Heiji's fiancée and a karuta champion. As Kazuha prepares to compete against Momiji in a tournament, a murder occurs with incriminating evidence pointing towards Momiji. This leads Conan and Heiji to delve into the secrets entwined with the competitive karuta world.