The Course of Empire
by Eric Flint

Description:
Conquered by the Jao twenty years ago, the Earth is shackled under alien tyranny--and threatened by the even more dangerous Ekhat, who are sending a genocidal extermination fleet to the solar system. Humanity's only chance rests with an unusual pair of allies: a young Jao prince, newly arrived to Terra to assume his duties, and a young human woman brought up amongst the Jao occupiers.

But both are under pressure from the opposing forces--a cruel Jao viceroy on one side, determined to drown all opposition in blood; a reckless human resistance on the other, perfectly prepared to shed it. Added to the mix is the fact that only by adopting some portions of human technology and using human sepoy troops can the haughty Jao hope to defeat the oncoming Ekhat attack--and then only by fighting the battle within the Sun itself.