The special will retell what happened on the day Shinichi's teenaged body was transformed into that of a child. It will add new material that was not in Gosho Aoyama's original manga or the first episode of the television anime two decades ago. The story begins when Shinichi sets up a date with Ran at the Tropical Land amusement park. It follows with Shinichi's encounter with Gin and the others at the park.
Viz publishes the original manga under the title Case Closed in North America (with Shinichi renamed as Jimmy), and it describes the beginning of the story:
Ghastly beheadings, bloody murders, and coldhearted child abductions! Precocious high school student Jimmy Kudo uses his keen powers of observation and astute intuition to solve mysteries that have left law enforcement officials baffled. Hot on the trail of a suspect, Jimmy is accosted from behind and fed a strange chemical which physically transforms him into a grade schooler! Taking on the pseudonym Conan Edogawa, he attempts to track down the people who did this to him. But until he finds a cure for his bizarre condition, Jimmy continues to help the police solve their toughest cases. Can you crack the case before Conan does?Funimation has been releasing the television anime series in North America, also under the title Case Closed