GALAXY EXPRESS 999: ETERNAL FANTASY

Based on the story by manga master Leiji Matsumoto (The Cockpit, Queen Emeraldas), the 55 minute featurette picks up one year after the events of Galaxy Express 999 in which a young boy named Tetsuro and his motherly companion Matel worked to rid the universe on the Mechanized Empire who had taken over Earth. (Source: AniDB) — Description from AniList community (anilist.co).