Heiji was invited to go to a real demon dog extermination, and invites Conan, Kogoro, and Ran to come with him and Kazuha.
Five years ago the womanizing chairman of the Inubushi group, Hisashi Inubushi, had died of terminal cancer. Due to his past habits, several people appeared, claiming to be related to Hisashi by presenting a picture of their mother with the president. Without the president or their mothers to confirm whether the claims were true or not, it became impossible to confirm or deny the claims. Regardless, the president's wife took in all eight people as her own adopted children. And now, with the president's wife ill herself, the inheritance was to be divided amongst the 8 children.
However, two out of eight had died in strange ways. One had died falling from the cliff, claiming that a fiery monster had assaulted him prior to the fall. Another had been assaulted by a dog on fire.
Heiji and Conan went to meet a man named Shinichi Kudo, but end up unable to meet with him because he was asleep. Thirty minutes later, they return to his room upon hearing a musical timer supposedly meant to wake him up, only to find his door sealed and Shinichi dead.
Murder
Location:Shinichi Kudo's room
Victim:Shinichi Kudo
Cause of death:Carbon monoxide poisoning
Suspects:Funae Abukawa
Shinichi Kudo was found dead due to carbon monoxide poisoning in his room, the door and windows sealed shut via duct tape. Carbon monoxide was produced by a burning charcoal grill.
The books stacked near the window(serving as a makeshift footstool) in a room of a man with a bad back.
The charcoal wasn't hot even when held, indicating that it had already finished burning a while ago.
The set-up would have logically taken longer than the thirty minutes.
The jaw had already began to stiffen, indicating that the man had been dead for longer than an hour.
Motive
A picture of Fubukawa's son was found inside the wardrobe door, and the culprit insisted Fubukawa follow their orders lest her son meet the same fate as Kudo.
Conclusion
Fubukawa breaks down, claiming that Kudou was already dead by the time she came in the afternoon. Fubukawa had answered the phone and heard a voice telling to her that she'd better hurry and save Kudou, locked in the wardrobe in his room. She did so, only to find the dead Kudou and a picture of her son. Shortly later, the mysterious person claiming to be a vengeful spirit called back to threaten Fubukawa into cooperating.
Takagi and Megure arrive, and Fubukawa informs them that when she found Kudou's body, he was dressed in a suit and necktie with its pin removed. In addition, from Kudou's mouth fell a pearl, supposedly from the necktie pin, which could be Kudou's dying message.