Dr. Jonas Cullen has spent his career as a groundbreaking physicist defying the odds. But on the best night of his life--the night his wife, Amanda, tells him they're finally having a baby--everything is taken away when a tragic car accident claims the lives of Amanda and their unborn child.

Gutted by pain, Jonas sets out to find a way to bring back Amanda--or rather, find a parallel universe in which she's still alive. But that's easier said than done. As Jonas comes to understand all too well, the universe favors certain outcomes...and Amanda's death is one of them.

Guggenheim's novel takes readers on a suspenseful journey, intercutting scenes of Jonas's frantic, present-day search across multiple realities with glimpses from the past of his unfolding romance and eventual marriage. Will Jonas and Amanda reunite in some other world, or will fate succeed in taking her from him forever?