The Detective Conan anime will celebrate its 20th anniversary with a brand-new two-hour television anime special this winter. Meitantei Conan Episode “One” Chiisakunatta Meitantei (Detective Conan Episode “One”: The Great Detective Who Shrank) recounting “the true first episode not seen by anyone!!”
The special will retell what happened on the day Shinichi’s teenaged body was transformed into that of a child. The story will include scenes we haven’t seen in the original manga or the first episode, allowing viewers to know what happened elsewhere that day. The project will be entirely realized under Aoyama’s supervision.
The first teaser for the special is set to be released on September 17.
source : Detective Conan Anime Gets New 2-Hour TV Special Recreating 1st Episode