Parallel Heat — Deidre Knight

Warrior and royal guardian Marco McKinley has been assigned a vital mission on Earth, where a war between human fighters and other-worldly soldiers is rising. But he's also been warned about twists of fate yet to come -- ones that will transform him into the enemy of his own people and appoint him the personal protector of beautiful soldier Thea Haven.

Little did Marco and Thea know, but they have met before in an alternate universe, and they are bound by betrayal and vengeance. Now, on a world at the brink of destruction, they feel only a forbidden passion and the unease that comes with it ...