Lost Fleet: Beyond the Frontier- Guardian Book 3

Admiral Geary's First Fleet of the Alliance has survived the journey deep into unexplored interstellar space, a voyage that led to the discovery of new alien species, including a new enemy and a possible ally. Now Geary's mission is to ensure the safety of the Midway Star System, which has revolted against the Syndicate Worlds empire - an empire that is on the brink of collapse.