At Ooka Momiji's request, Conan and Heiji solve the code left to four sons by their mother who worked for a wealthy family for many years. They arrive at Haido Harbor Warehouse 4, where they find a man on the ground bleeding from the head and three others standing around him. They are the brothers who received the code from their mother, and the dead man is the eldest brother. They were invited to the warehouse by the eldest brother, but he was already dead by the time the first brother arrived, and the other two met up with him after that. Based on the metal frame glasses on the ground nearby, Conan and Heiji believe this was a murder...