By the Light of the Moon - Dean Koontz

Dylan O'Conner is launched onto a nightmarish odyssey when he is seemingly randomly attacked and injected with a mysterious substance. What follows, as he and his autistic brother try and figure out what has happened, will take them into the path of another victim of the "doctor" who injected Dylan, and together they find themselves on the run, with only 24 hours to escape from the fleet of black, unmarked vehicles that is pursuing them.