The Colonies (2004)

Publisher Blurb:

Fighting for freedom on occupied Earth. The Virimar landed eighty years ago, their mothership crippled in a partially successful attempt to deflect a comet from Earth. We thought they were our saviors. We were wrong. They had other plans, and found more than enough human hands willing to help subjugate their brethren. Now it's time to fight back. Think of a French Resistance-style background, but make it world-wide and high-tech. Adventurers are largely drawn from Earth's pre-Virimar off-world colonies, dropping to Earth in stealth pods and trying to discern the motives and plans of the enigmatic Viramar, while building enough support to make an invasion possible and avoiding the collaborator secret police. Not an easy life, and if you're not careful, not a long one either...