The Oort Perimeter (Earthfleet Saga, #1)

Born of a need to protect their homeworld, Earthfleet, the military arm of the Society, struggles continuously to ensure the safety of Earth and all who live on it. But a dark force moves within the galaxy, one who wishes to use Earth as a pawn in its quest for power. In a struggle for survival, the Society, Earthfleet and their allies must race against time to uncover the identity of this dark force, before it can destroy Earth, and the nine races. Failure means extinction of the human race.