When Cars Fall From The Sky - John Wheeler Novels, #1

Twenty-two years after an alien race has successfully invaded our world, John Wheeler, a down on his luck private investigator, is sitting in the baking heat of what has become the new 'normal' of earth's changed climate. A beautiful woman approaches. She hands him a thick envelope full of cash and wants help finding her missing brother. Wheeler needs the money. He should have said, "No". Ride along with Wheeler as he discovers a world of hurt, navigating parallel dimensions, stumbling into worm holes, dodging the chaos of state sanctoned violence, and avoiding the police and aliens who mean to stop his investigation by any means possible.
John Wheeler vol. 1