Collide — Melissa West

Military legacy Ari Alexander has survived alien spies, WWIV, and a changing world order. But when the new leader of Earth uses Jackson -- the only boy she's ever let herself care about -- to get to her, Ari has no choice but to surrender. To free Jackson, she agrees to travel to the national bases to train others to fight. What she discovers is a land riddled with dying people. Ari has the power to heal by turning the fighters into aliens-half-breeds like her. If she succeeds, together, they have a chance at overthrowing the alien leader, Zeus. But if she fails, everyone she holds dear will be wiped away forever. Once again, everything Ari's come to believe is thrown into question. In a world of uncertainty, loyalties are tested, lies are uncovered, and no one can be trusted. If Ari and Jackson have any hope at survival and at preserving a life for the future, they must fight the final war with their eyes wide open.