Conan, Ran, and Sonoko meet up with Eisuke who is looking for his long lost sister. His sister looks identical to the famous newscaster Rena Mizunashi, but Eisuke claims they are not the same person. They head to a fan of Rena to make sure, but when Ran tries to contact him, a mysterious man continues to answer the phone claiming she dialed the wrong number. They head to his mother's house as a last resort where they discover the fan is on vacation and the mother might be victim of remittance fraud.

The mansion owner, Kakuzo Okudaira, explains to Kogoro the person who murdered his son a year ago might be someone living in his household and the murderer might return to kill him next. Conan, Kogoro, and the rest of the group is introduced to Kakuzo's wife, Eiko, and then shown to the living room. The group rushes to Kakuzo's room after a power outage and a loud crash. Kakuzo screams to not come in the room, but the butler and maid disobey to find Kakuzo hanged and his 50 million yen vase broken. The police determine Kakuzo was murdered and attempt to analyze a blood covered book that could be Kakuzo's dying message.