"Are you happy with your life?"

Those are the last words Jason Dessen hears before the masked abductor knocks him unconscious. Before a man smiles down at him and says, "Welcome back, my friend." In this world he's woken up to, Jason's life is not the one he knows. His wife is not his wife. His son was never born. And Jason is not an ordinary college physics professor, but a celebrated genius who has achieved something remarkable. Something impossible.

Is it this world or the other that's the dream? The answers lie in a journey more wondrous and horrifying than anything he could have imagined.