From another Thread
It starts after act 3 and ilium.
The Republic is pushing the Empire back on all fronts due to the aggressive strategy put forward by the new Chancellor. The Empire is resorting to scorched earth in order to slow done the Republic and give them time to bring in fresh Alien troops to fortress worlds, such as Duro.
Meanwhile the Republic is focusing on the Core and Inner rim, The Empire establishes a secret base on Byss and the then lunches a devastating assault on Tython destroying the jedi Temple and the ecosphere, ie turns in to a dust bowl.
Master Shan disappears, and when Garza wants to Strike back against Byss, will leaving the rim vulnerable, the Chancellor tries to have her removed. Garza then arrests the senate and the Republic falls into civil war.
Act 3 is the Empire consolidating it's positions,
While the Republic class capture Garza and prepare to fight the Sith Empire,