After learning that his father Gajirou was going to give all his fortune to his mistress, Genzou went to her house and burned it with her inside. Rumors are that her child managed to escape it and is after the Kurokawa brothers.
The culprit is the fourth brother Jirou Kurokawa. There was no way an outsider could have gone on the island when the ferry was not in use and when the harbour was the only possible way of berthing. Thus, it all made sense when the culprit was Jirou, who was unsuspected and could freely move around. The proof is the mist that disappeared on the window in Jirou's room, which proves he left his room to shoot Ichirou. His motive was that he was always bullied by his brothers and that he was the illegitimate son and that Naruse was just a scapegoat to him.
Jirou attempts again to kill his brother, but is stopped by Conan's kick shoes. Afterwards, he is taken away and apologizes to his brother. Some time later, Kogoro and Conan visit him and prison and inform him that the real Naruse is living a happy life with his grandchildren, bringing some peace to Jirou.
Conan and the Detective Boys corner Wataru as Takumi's killer. He sat far away from his partner on purpose, so he could pull on a string he attached to the suitcase above Takumi when the train will make a sharp stop. The suitcase would then fall and break Takumi's neck and he would not be suspected since he is too far away. The proof is the marks on the suitcase handles and all the fishing line he has stuck inside his guitar. After the Detective Boys solve the case, they want to appear on the television as the case-solvers, but when the detective asks for their names, Conan, who fears Ran and Kogoro will see him on the television, runs away with the others back inside the train.
It turns out the hit and run was not directed at Ran, but towards the clerk working atHandmade. Some time ago, she helped an old man and the old man wanted to thank her for her deed, so he left her a big chunk of his inheritance. Since the clerk kept refusing the inheritance, the old man wanted to come have her sign the papers the next day. The old man's relative, who was not happy with that, wanted to eliminate the clerk before she could get sign the papers the next day, but mistook Ran for her, since Ran bought her handmade only-one-in-the-world jacket.
Conan figures this out and goes back to the hospital, where he sees a lot of smoke coming from the men's bathroom. He finds a lot of used cigarettes in there, and figures out the culprit was waiting in the toilet for the curfew to come, so he could kill Ran without being seen, before she could sign the papers. Conan knocks him out before he can do so by kicking a hospital bed, hurting himself in the process. He thus ends up confined to a hospital bed, just like Ran.
Conan figures out that the culprit must find a location to look at all his crimes happen. The only location that stood out was Beika Building, the tallest in the neighborhood. After gathering information from the security guard, he figures out that the culprit can only be part of the cleaning company, since the building is closed on Tuesday nights. The only employee that stood out was Shirou Namiki, a heavy smoker who often left during his shifts. At his apartment, Conan finds the evidence that pins him to the crime, newspaper clipouts of the arsons.
Conan then finds Shirou trying to light a fire, but stops him by kicking a ball in his face. The next day, Conan and Ran comment on the man's arrest, while Kogoro burns himself by dropping his cigarette on his newspaper.
