Kogoro Mouri accepts a case to help to find out who has been sending threatening phone calls and letters. On the way to the man's apartment with his friend, Kogoro and Conan witness the man fall to his death.
Conan finds out that the culprit is Joji Ueda and solves the case. Yoshimura has the habit to use the warehouse's stairs next door to get to his unit in the condo because every night the condo's elevator stops at every floor for security purposes. The space between his balcony and the warehouse's courtyard is within a jumping distance, making it easier for him to go to his unit. The culprit knows this habit and used it for the murder to make it look like an accident. He rearranged his room furnitures to make the room similar to Yoshikawa's room. While they're drinking whiskey together, Ueda put some sleeping pills in Yoshimura's drink to knock him out and brought Yoshimura to the culprit's unit, laid him on the bed, and closed the room's light so that Yoshimura wouldn't notice that he wasn't in his unit. Ueda used the Unemoto, a florist, for his plan. He ordered flowers to be delivered to his unit at 7pm. Ueda called Yoshimura to wake him up and while they were talking to the phone, the florist knocked on the door to deliver the flowers because the doorbell is broken. Mistaking it for the man after him, he tried jumping to the next building as usual. He fell to his death.
