Night is dangerous. Day is deadly. On a planet that rotates the wrong way, where day and night last thirty years, humans can only live in the twilight zone, constantly moving to stay ahead of the dark night and the cruel Nocturnals that call it home. Joah Cadshaw used to retrieve people the Nocturnals had taken, until his wife came back broken. Now, sent out west to spread word of the coming Move, he finds signs of another person gone missing - a young boy. If Joah wants to save the boy, he must face the monsters who haunt his dreams.