After the One Year War and subsequent wars with the last remnants of the Principality of Zeon, the Earth Federation formed a special military force to prevent space colonies from revolting against the Federation. Thus, the Titans were born. Eight years have passed since the end of the One Year War and now the tables have turned. The once good Earth Federation is now more corrupt than ever and will turn the other way even when its special force, the Titans, commit atrocities like gassing millions of civilians to their deaths. Because of this abuse of authority the Anti-Earth Union Group (AEUG) is formed from the breaking off of many Federation politicians and military who oppose the Titans, and they will ally with former members of the Principality of Zeon, who dislike the oppression and tyranny towards the space colonies. This where the story begins. Many heroes from the One Year War, like Amuro Ray, Char Aznable, Bright Noa, Hayato Kobayashi, and Quattro Bajeena (Char Aznable), as well as new heroes (Camille Vidan, Emma Sheen, Katz Kobayashi) will fight the Titans' Bask Ohm, Jerid Mesa, Paptimus Scirocco and Yazan Gable, and the Axis' (former Zeon) Haman Kahn, to see who will win the war to end tyranny.
—fml_lopez