Following the murder in Tokyo, Heiji and Kazuha accompany Otaki with Conan and company to investigate a "vampire" curse on a family as a request from Hattori's father to Otaki.
At the arrival of the mansion, it is reavealed that the butler submitted the request to Heiji's father. He requested a detective to be present at the inheritance ceremony.
Murder (Past)
Location:Tree
Victim:Shimizu
Cause of death:Blood loss
Suspects:Hakuya Torakura
Murder
Location:Torakura household
Victim:Hakuya Torakura
Cause of death:Stab wound
Suspects:Rikushige Koga, Ruri Torakura, Asanobu Torakura, Kamiyo Torakura, Jouhei Hagawa, Kishiharu Torakura, Mina Torakura, and Hikaru Hinohara
Part 2
Murder
Location:Torakura household
Victim:Asanobu Torakura
Cause of death:Slit wound on the throat
Suspects:Rikushige Koga, Ruri Torakura, Kamiyo Torakura, Jouhei Hagawa, Kishiharu Torakura, Mina Torakura, and Hikaru Hinohara
Part 3
Murder
Location:Forest near Torakura household
Victim:Kamiyo Torakura
Cause of death:Strangulation
Suspects:Rikushige Koga, Ruri Torakura, Jouhei Hagawa, Kishiharu Torakura, Mina Torakura, and Hikaru Hinohara
The culprit is Jouhei Hagawa. Hikaru Hinohara was actually Hakuya's daughter due to the will and DNA report found in his room. The tunnel that he was escaping in was made for Hikaru. Hakuya bought clothes as gifts to Hikaru because he wants to find out her body size to see how wide to make the tunnel. He wanted Hikaru to do the serial murder plan that he made for her. All the tricks done was he was to tell her when she was at the foreign torture in the morning but Jouhei intercepted the message on her phone. Foreseeing that he'd get back together with Mina and he did the plan and try to get the money that way. Hakuya committed suicide to make the tricks work. Along with the plan there is his cellphone, the keys the freezer and the switch to blow up the tunnel. The motive was avenge Youko whose "accidental" death was actually plotted by Jouhei, Shimizu, Kamiyo and Asanobu. Since Hakuya was a doctor he must've drugged Shimizu with something to thin out her blood and drew it out from artery at her neck with a catheter. Jouhei snuck over to he hding space underneath the coffin and retreived the head using a secret passage.
