David, who was one of the worst threats the Animorphs ever had to face, is only a memory now. He tried to kill Tobias, and almost killed Jake, but the Animorphs trapped him in rat morph and placed him on a deserted island. Never to be heard from again.
Or so they thought. David, driven insane by his experiences, is back. He managed to escape the island and is after Rachel. Sure, a rat isn't much of a trouble -- but Crayak, the Ellimist's big red eye of an enemy, is back as well. The Animorphs outsmarted David before, but Rachel, by herself, may not be able to win this battle....