Conan witnesses office worker Fukurokoji Sadao fall off the roof of a ten story building. Fukurokoji seems to be falling directly towards office worker Komatsu Hitoshi, who is standing in the alleyway, but Conan kicks a ball into him, and he falls into a nearby heap of garbage and survives. At first it was thought to be an attempted suicide by Fukurokoji, but Inspector Megure determines someone carried the plastered drunk Fukurokoji to the roof and pushed him off, making it an attempted murder. After investigating the rooftop, Conan questions Komatsu, and he deduces that the murderer was attempting to kill not only Fukurokoji, but Komatsu as well. He tries to find someone bearing a grudge against them both, but...