Universal Century 0068. Casval and Artesia are the orphaned children of Deikun, who preached the reformation of humanity through advancement into outer space and independence from the Earth Federation government.

With Deikun's death, conflict intensifies between the Zabi and Ral families. To escape the political strife, Deikun's orphaned children Casval and Artesia say farewell to their mother and depart for Earth with Jimba Ral.

Universal Century 0071. Changing their names to Édouard and Sayla, Casval and Artesia have begun new lives on Earth as the children of Teabolo Mass, but they are attacked by assassins dispatched by Kycilia.

Sayla and Édouard are grief-stricken by the death of their imprisoned mother, and Édouard swears revenge upon the Zabis. He learns that the Aznable family's son Char is entering the Zeon military academy, and devises a plan.