Avenger - Sovereign Stars, #1

Five years after physicist Mark Holder discovered the Slipstream Drive in 2058, humanity reached for the stars and began to colonize the galaxy. For centuries, humans continued to populate system after system without encountering intelligent alien life. Some twelve hundred years later, after many generations of relative peace, in the year 3278, human space is invaded by a powerful and mysterious enemy.
To these invaders the very concept of free will is heresy. Their crusade-to eradicate humanity. The war begins, and the fight for the survival of the human race is on. Book 1 of Sovereign Stars, Avenger, is the first novel in a gripping, action-filled military space opera in which Avenger, under the command of Knight Captain Richard Morian, is sent to one of the outer star systems on a rescue mission.
What he discovers there suggests the entire Orso Carrier Group is destined for annihilation.