Gray Apocalypse

The human race is about to be destroyed by the Breeder Grays and replaced by millions of hybrids--half human, half alien--the Breeders have created. The weapon of destruction: an enormous asteroid the aliens have diverted to strike earth. Only Michael Kendon, a renegade assassin and sole survivor of a crushed resistance movement, can keep it from happening.
Kendon has only three days to locate a powerful weapon designed to deflect the asteroid, a gravity-beam device fueled by the same exotic element that propels the Breeder spacecraft. But to find the weapon, he must first gain the loyalty of a woman whose father, the creator of the weapon, he was forced to kill.
During their heart-pounding quest, Kendon's lethal skills keep him and Laura Meller alive and on the move, but his extraordinary mental abilities prove the most bedeviling to the Breeders and their human collaborators. Gray Apocalypse is a warp-speed journey into the heart of universe darkness, and it is an unforgettable tale of human survival and personal redemption.