An astonishing, relentlessly surprising thriller from the author of the bestselling Wayward Pines trilogy. "Are you happy with your life?" These are the last words Jason Dessen hears before the masked kidnapper knocks him unconscious. He awakens to find himself strapped to a gurney, surrounded by strangers in protective suits. A man Jason has never met smiles at him and says, "Welcome back, my friend." In this world he has woken up in, 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 physics professor, but a celebrated genius who has achieved something remarkable. Something impossible. Is this world or the other one the dream? And even if the home he remembers is real, how can Jason possibly return to the family he loves? The answers lie in a journey that is more wondrous and terrifying than anything else.