Edogawa Conan Shissou Jiken: Shijou Saiaku no Futsukakan

名めい探偵たんていコナン 江戸川えどがわコナン失踪しっそー事件じけん～～史上しじょー最悪さいあくの二に日間にちかん～～

The anime special celebrates the 20th anniversary of Gosho Aoyama's original manga, and it recounts a previously untold story from Conan's past.