Attack on Phoenix — Megg Jensen

Two hundred years ago, an interplanetary expedition crashed on a deserted planet. Their ship was destroyed. Their technology lost. They built a new society while they waited for rescue. It never came. Instead they caught the attention of the dragzhi, an aggressive alien species, and found themselves in the midst of a war they were doomed to lose. Torsten Vikker, a soldier who'd rather read than fight, is on a mission to recover an artifact rumored to have the power to defeat the dragzhi. Rell, a woman raised in a cult, will stop at nothing to keep him away from what she holds sacred. Yet, only together can they hope to save humanity from utter annihilation.