When a mysterious woman pulls Mark from the edge of suicide, he thinks it's a miracle. But his savior is no angel-she is a demon, bound to him by a paradox of mutual salvation. Now, she offers him the ultimate escape: travel back to the moment his parents first met and prevent their union. By erasing his own birth, the lifetime of agonising pain that drove him to the edge will never happen. But as he prepares to undo his existence, he must face the terrifying cost of reality. What is the ultimate price of being?