Conan, Ran, and Sonoko arrive at the Suzuki Balloon Festival, a national hot air balloon event. During the race, reigning champion Mizuguchi Shingo's balloon is struck by Okuda Akihiro's and begins falling. As the balloon descends, his wife Mizuguchi Arisa falls from the balloon to her death. Because Mizuguchi and Okuda fought before the race, the police suspect Okuda deliberately crashed into Mizuguchi's balloon. Okuda insists it was an accident, but based on the condition of Okuda's balloon, they determine it wasn't an accident but a murder...