The Lost Fleet: Beyond the Frontier: Guardian is the Third book in the Beyond the Frontier series, the continuation of Jack Campbell's The Lost Fleet series, published in 2013.
Summary[]
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.
To complicate matters further, Geary also needs to return safely to Alliance space not only with representatives of the Dancers, an alien species, but also with Invincible, a captured warship that could possibly be the most valuable object in human history. Despite the peace treaty that Geary must adhere to at all costs, the Syndicate Worlds regime threatens to make the fleet’s journey back gruelling and perilous.
The UK Cover of The Lost Fleet: Beyond the Frontier: Guardian
And even if Geary escorts Invincible and the Dancers’ representatives safely unharmed, the Syndics’ attempts to spread dissent and political unrest may have already sown the seeds of the Alliance’s destruction...