A woman, Kae Nishiwaki, comes to the Mori Detective Agency where Conan and Kogoro are. She came to ask Kogoro for help, saying that someone had broken into her room while she was at work. The intruder, who appeared about a month ago, is not a burglar, but is said to leave gifts in the room. She came to Kogoro's office because she thought the police would not believe her story because of its strangeness. Conan and Kogoro arrive at Kae's apartment and find a trunk with a ribbon on the front door. Thinking it was a new present from the intruder, Kogoro opened it and found the body of Ryuko Kusakabe, bleeding from the head, stuffed inside...