Road Trip — C.M. Simpson

When Melange feels the pull of utter dread emanating from a road train parked at a rest stop near her home, she investigates. She has no intention of being trapped in the cab on the driver's unexpected return, nor of being stuck in the truck when he is murdered during the first delivery. But she can't stay there. She's discovered the prisoners that were the source of the dread, and the trolls are coming to take them away. With time running short, she has to find a way to avoid capture, and summon help -- and that means getting past the troll and humans standing guard.