The Sith Empire hasn't been heard from for many years. After the Separatist attack the colony of Lyra the Sith Empire enters the Clone Wars. Darth Blade former apprentice to Darth Rune will become a hero to the Empire before he's betrayed and exiled. He creates a PMC and helps the Republic and later the Alliance to Restore the Republic.

The Odyssey was a prototype ship built with some new technology it had a ten year mission to find the 13 colony of Kobol until the Cylons attack the colonies. it join with the Battlestar Galactica and its civilian fleet at Ragnar Anchorage and together they go and search for Earth. the Odyssey sends out patrols every day to find out if anything is ahead of them.

The 5th Mobile Infantry Division are sent to the planet Terra deep in the Arachnid Quarantine Zone to setup a base once there the fleet leaves them alone. They thought the planet was bug free but they're wrong. However, before Terra they have several campaigns before they're sent to Terra.