Are you happy in your life?'

Those are the last words Jason Dessen hears before the masked abductor knocks him unconscious.

Before he awakes to find himself strapped to a gurney, surrounded by strangers in hazmat suits.

Before the man he's never met smiles down at him and says, 'Welcome back.'

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.

In this other life, Jason has created a box. Transport into infinite alternate universes – every possible outcome of his life, one behind each door. In this other life, Jason chose a door. And he stole the life he wanted.