A series of short manga stories, revealing important background details about the five young Gundam pilots and Relena Peacecraft. Episode Zero explains such details from the series as the origin of Duo Maxwell's nickname "Shinigami" (Grim Reaper/God of Death), Quatre Raberba Winner's link with the Maganac mercenaries, and other elements that would go on to play major roles in the Gundam Wing anime and its sequel, Endless Waltz.

Before the outbreak of the colony war, forces were at work shaping the future and preparing its players for the final game. As children, each of the Gundam pilots endured hardships that would have broken the will of any normal person. Gundam pilots Duo Maxwell, Heero Yuy, Trowa Barton, Quatre Rabbera Winner and Chang Wufei have endured more pain and difficulties than most people experience in a lifetime. But not even their comrades in arms could have known about the even more tumultuous childhoods as war orphans and other hardships.