Our world has been stalked by Shadow. It has been shattered by Plague.

Now, it is threatened by the most dangerous power of all: the Impossible.

Sienna Farren is a Mapwalker. And she is suffering.

Still burdened by the growing Shadow magic within her. Still missing the touch of Finn, the Borderlander she loves. Still agonized over her decision to shut the borders between our world and the Borderlands – the shadow-world of madness and magic that has threatened to overwhelm us since the beginning of history.

It was the only way to seal the portal between the worlds, and to save our world from the annihilating power of the Map of Plagues. But the decision meant all-but-certain doom for the Borderlands, including Finn and his people.

Even worse, the choice may have been for nothing, because now both worlds are suffering. The Borderlands has fallen under the spell of a magical drug that turns its people into abominations. And our world is suffocating without the vitality and magic of the Borderlands.

Once again, Sienna must risk all – to use her magic and save the worlds. Because she has discovered a new map. A map that could reopen the portals between us and the Borderlands. A map that could save us... or doom the universe.

Or perhaps both. Because Sienna Farren now hunts for the Map of the Impossible, and with its power any dream – or nightmare – could come true.

Begun in Map of Shadows and continued in Map of Plagues, the Mapwalker trilogy concludes with Map of the Impossible by New York Times and USA Today bestselling author J.F. Penn. Get your copy now, and find out why this blend of magic, mystery, adventure, and history is like nothing you've ever seen before!