Hung Out to Dry
The imperial leadership of Earth decreed that all defense focus on protecting the Earth, and that the outlying colonies on Venus, Mars, and the moon only existed to provide resources for that defense. After centuries of second class citizenship and exploitation, Mars natives begin to revolt, with the help of alien technology found deep in Martian mines. Yes, it sounds as if the Dynamix team has seen a few too many Schwarzenegger movies (Terminator and Total Recall), but it really does make for an interesting story. As the colonists on Mars begin their revolt with high tech weapons, the Emperor sends armies to quell the rebellion. At this point, the Cybrids, who have been lying in wait, sense a golden opportunity to smash the Earth.
Also from the cutscene, this shows Caanan and his invasion force
In Starsiege you'll be able to play out two long, linear campaigns. One has you rising up the ranks of the Martian rebels while fighting the Imperial forces from Earth. Amidst rumors of Cybrid activity you work to free Mars from the oppression of the Imperial government. The second campaign puts you into the Cybrid side of the war, as you try to fight your way back to Earth. Don't expect to waltz through the missions and beat the game - winning takes careful planning and choosing the proper weapon/item loadout for your HERC.