In A.G. 101, The war between the Earth Federation Forces and an Unknown Enemy would begin when the latter destroyed the space colony Angel, a tragedy that would later known as "The Day the Angel Fell." 7 years later, when the colony Ovan was being attacked by the UE, Flit Asuno's dying mother provided him with their family's heirloom, the AGE Device, which contains schematics for a legendary Mobile Suit known as "The Gundam." Having spent the next 7 years working to develop this weapon, he soon must put it to the test when a fleet of UEs invades his new home colony Nora, threatening the lives of his friends.

The U.E. attack of Nora has left the colony in imminent collapse. The Federation commander of the colony, Hendrick Bruzar, came up with a plan to use the flagship battleship, Diva, to save the colony core, thereby enabling the colony inhabitants to escape the destruction. However, the captain of the Diva has other plans. Meanwhile, Flit tries to escape the colony while piloting the Gundam, but comes upon a stranded girl named Yurin, who seems to have mysterious powers of her own.