The Sith Empire had won victory after victory in the Great War. But despite the Sith Emperor's planning, the Empire had also endured setbacks from stubborn Republic defenders. To shatter the Republic's morale, Imperial forces led by the newly-promoted Darth Malgus descended on the peaceful Core World of Alderaan. The surprise attack left Alderaan in flames.
Alderaan was little more than a transfer station for Republic soldiers on leave, though it also had a number of Republic military hospitals. There was no way the Empire could have foreseen that Captain Jace Malcom and Havoc Squad--the Republic's elite Special Forces unit--would be on planet as the attack came. Jace organized an armed stand against the Empire and signaled the Republic.
During an ambush in Alderaan's snowy forests, Captain Malcom and Satele Shan--the Jedi who would become Grand Master of the order--fought and defeated Darth Malgus. The tide was turned; the Republic fleet arrived soon afterwards, securing Alderaan, and the injured Malgus was secretly evacuated by fleeing Imperial forces.