Thomas Llewellyn and his cousin Emily have returned to the Realm of Imagination, at the express invitation of Belactacus and the Council of Reality. They have been tasked with finding and defeating a dangerous and powerful young man, a human, just like them. Left to his own devices, he could devastate the world of the Figments. Thomas and Emily must master the powers they discovered on their first visit and use them to stop Magnus.

It seems, however, that the Realm of Imagination is not the same place they remember. Some consider the humans to be most unwelcome, and once again, there are things that Thomas and Emily are not being told. Can they find Magnus and bring him back to the human world? Can they trust the very people they have come to help? The Figment Wars have raged on since the beginning. Now it is time for them to end, one way or another.