Space Alien War

At least they're primates. That was Commander Riniana Tiana's first thought when she saw the primitive - but sentient - humans of Earth. She should be able to fit in...After all, her own species is primatal too. And she'd only come here to save them from invasion...But humans don't have tails. And most of them seem extremely jealous of hers! Using the curious custom of clothing, Tiana hides her tail, passes for human and pursues the alien invaders in a desperate struggle to save an ungrateful planet.

No one on Earth knows the seeds of the world’s destruction just fell from space. Tiana knows what duty means though. It's why all her friends are dead. Alone on a primitive world. All her all her technology at the bottom of the ocean. Outnumbered by deadly enemies only she can bring to justice. If she fails her mission now, another sentient species will fall. And the Tyrant Empire will rise again - because Earth has just been infected with a fatal parasite.

Humanity, previously dependent on the K'Tai for its Redlazore, discovers vast resources of the most valuable mineral in the galaxy on Agate and is now free to expand across the stars: Redlazore is also the key component to faster-than-light travel. The planet Agate is, however, the human colony-world which lies perilously close to the K'Tai Imperium, and the K'Tai resolve to put the upstart humans back in their place. The K'Tai Imperium invades Agate. On the ground, in the midst of the whirlwind conflict is the Carter family.