In Queens, New York, 22-year-old real estate agent Madison May is showing a house. The buyer, a man she's never met, is friendly, engaging . . . and claims to be her soulmate from a parallel life. She's in danger, he tells her. He's come to save her. Later that day, newspaper journalist Felicity Staples is assigned to report on Madison May's murder. Discontent with her own life, Felicity finds herself drawn into a shocking conspiracy involving a powerful group who have harnessed the ability to slip between lives - to move between one version of reality to another. On the run, turned into an imposter in her own life, Felicity is forced to seek the truth behind Madison May, the woman who is murdered over and over, in different ways, wherever she goes. For only by saving Madison May can Felicity reassemble the broken pieces of herself.