Fate Unexpected - Earth Defender, #1

A summer storm of red rain changed life as Kylah knew it, and her in ways she couldn't imagine. Humans around the world sickened and died, or turned into wild creatures with red eyes that hungered for flesh. Her planet was on the verge of extinction, and there was nothing anybody could do about it. Rune, a Dracan mercenary, had signed on with the Xphens to fight for them during the Earth conquest.
Having Kylah capture him changed everything. She had him questioning which side he wanted to be on. Kylah finds herself drawn to the large cat-eyed alien. Fleeing with Rune to the Cascade mountain range, she lets her feelings for him cloud her judgment. From two different planets, theirs is a relationship that could end before it had a chance to start.