Trial by fire

"When interstellar diplomat and intelligence operative Caine Riordan returns from humanity's first encounter with aliens, war erupts. With Earth's fleet shattered by a sneak attack and its survivors fighting for their lives, Caine must rely upon both his first contact and weaponry skills to contend with alien enemy but finds all is not as it seems. What if something even worse is on the way? It could be that Earth's attacker's harrowing memories of a long-past war makes them willing to do anything to keep it from starting over again--even if that means exterminating the human race"--