Mobile Suit Gundam 0083: Stardust Memory - The Mayfly of Space  

Kidou Senshi Gundam 0083: Stardust Memory - Uchuu no Kagerou, Mobile Suit Gundam 0083: Stardust Memory Cima Special, 機動戦士ガンダム 0083 スターダストメモリー 宇宙の蜉蝣, Mobile Suit Gundam 0083: Stardust Memory - Mayfly of Space

In episode 13, mayfly shows flashbacks of cimas' past as she reflects on what happened before the events in that episode. we learn that cima and her unit used g-3 nerve gas to poison a side 5 colony, following orders but being treated poorly by their own people afterwards for committing such an act. at war's end, cima's superior refused to let her return home to mahal, which had been transformed into a weapon, leaving her and her men without shelter.