During a roller coaster ride, a man loses his head. Shinichi and his childhood friend (girlfriend), Ran, were also on the ride, sitting if front of the man. It was decided that it is a murder and the murderer was the man's girlfriend by Detective Megure. Shinichi said that the murderer was the the girl sitting in front of Shinichi and Ran. The two man in black sitting behind the victim weren't suspects because of lack of motive. Only someone who was an athelete could have killed by sitting two seats in front of the victim. The murder weapon was a large hook and a piano wire. Hooking her legs on to the safety bar, she leaned over and slipped the piano noose around the victim's neck, let the hook go allowing it to catch onto the track. The speed of the coaster ripped the man's head off.

Later on, Shinichi spots one of two men who were also on the ride. Thinking it might be another case, Shinichi tells Ran to go home before him and that he's talk to her later. Ran sensing something wrong, doesn't want him to go. In a hidden part of the amusement park, two men are making a deal, one being the black clothed man, the other being some company president being blackmailed. Just then, the second man in black, hit Shinichi from behind and gave him an experimental drug. Leaving him for dead, Shinichi passed out from the immense pain... Coming to, a police officer ask him if he was alright....calling him a little boy at the same time....