Oblivion
(Book)

"The war with the profoundly alien Arduans has ended, and the Arduans have come to call humanity their allies. Most of them--the Arduan warrior caste refuses to accept defeat. Now known as the Kaituni, they are waging a war of extermination against all members of the pan-Sentient Union, human and Arduan alike. What's more, the Kaituni have an unexpected weapon in their arsenal: the alien Arachnids, once thought driven to extinction. The Kaituni drive the Arachnid fleet ahead of them, inflicting untold damage. The war has been marked by retreat on the side of the pan-Sentient Union. It seems the best they can do is minimize their losses. But now the Arachnids and the Kaituni are at the doorstep to the Heart Worlds, Sol, and Earth: Alpha Centauri. The odds look bleak. But Admiral Ian Trevayne and Commodore Ossian Wethermere have faced down long odds in the past. It's time to take a stand, for Earth, for humanity. and for the pan-Sentient Union!"--Provided by publisher.