Case Closed Episode "One": The Great Detective Turned Small (名探偵コナン エピソードONE 小さくなった名探偵 Meitantei Conan Episode One: Chiisaku Natta Meitantei) is a 2016 anime special based on the Case Closed anime. It premiered in Japan on December 9, 2016. Discotek Media licensed the special and Bang Zoom! Entertainment produced the English Dub of the special, which was released on DVD/Blu-Ray on July 28, 2020.
It all started when Ran Mouri lost her smartphone. Shinichi Kudo, her would-be boyfriend, promises to replace it, but the high schooler is already making his name as a consulting detective for the police; when he abruptly leaves her karate tournament to skillfully solve a high-society murder case, Shinichi's going to have a take Ran on a special date to get back on her good side. A colorful amusement park beckons-- and so does a horrifying act of homicide! In pursuing this new murder mystery, Shinichi stumbles across the shadowy Black Organization, a crime syndicate that attempts to silence the gifted sleuth the only way they can without attracting attention-- by force-feeding him a strange drug with unknown properties. Now, Shinichi finds himself younger--so much younger, in fact, that his police allies don't even recognize him! Armed with nothing but his wits and a brand new identity as Conan Edogawa, boy detective, Kudo takes off in pursuit of justice, answers, and someday, a return to his original age.