When he is eight years old, Alfie Logan discovers the magical ability to get a second chance at everything. He can undo any moment and live it again. The one catch: he must accept the consequences of his second try - for better or worse.

He grows up correcting his mistakes and saving himself from adolescent embarrassments. He even takes foolishly dangerous risks, just to see what it's like to come close to death, before tapping back to safety. Eventually, Alfie turns his gift to his love life, studying his crushes and going back to make himself more appealing.

In time, he falls deeply in love with Gianna, the woman he believes is the one. He seems to find contentment. But as the years pass, Alfie's eye begins to wander.

Which is when he learns a lone caveat to his power: once he undoes a love, that person can never fall in love with him again. Knowing if he gives into to temptation, he will risk losing what he has with Gianna, Alfie makes a choice that changes his life forever. The book begins many years later, after an ailing Alfie is arrested for allegedly cheating and winning millions at a casino roulette wheel.

As a curious detective interrogates him, he slowly uncovers Alfie's incredible story, and its most unlikely conclusion.