The story follows about a boy named as Shinichi Kudō that solved a case at a mansion. The next day, on his way to school, his case was all over the news and was being satisfied by that. His best friend Ran Mōri later showed up walking their way to school. At school, Ran remembers what Shinichi promised her, but seems to have forgotten. Shinichi does remember it later, which on the next day, the two went to Tropical Land, a theme park located in Beika City. There a man has been decapitated while they where in the roller coaster. Shinichi solved the case, which after solving the case, he is following one of the suspicious men that he has seen on the roller coaster. There he finds a shocking discovery, but didn't noticed his partner which Shinichi has been smacked unconscious. The man in black gives Shinichi a poison which turns his body into a elementary kid.JP: ジェットコースター殺人事件 (Jet Coaster Satsujin Jiken)
EN: Roller Coaster Murder Case (a.k.a. The Big Shrink)