After Life by Melissa de la Cruz

The Blue Bloods are back…more fanged and fabulous than ever.

After defeating Lucifer and sacrificing the love of her life, Jack, Schuyler wakes up back in New York safe and sound. Only it’s not quite the New York she knows, and she’s not in her regular body. She looks different and feels different and so does everyone else. Schuyler soon discovers that in this world, her best friend has a different last name, her parents are both alive and well and one of them is an entirely different person, and the love of her life? Not so dead after all. The catch? Jack has no idea who she is.
As it turns out, Schuyler is not in her New York. She’s not even in her universe. This is an alternate reality. One where Lucifer is alive and well and acting as mayor of New York, Blue Bloods are luring humans to clinics to drain their blood, and Jack is Lucifer’s right hand man. Just when she thinks all is lost, Schuyler is contacted by a familiar friend—the Silver Blood, Kingsley. The Kingsley from her world. He actually remembers the Schuyler she used to be! But he also has a theory, and it’s one she doesn’t like. That Schuyler was sent here to defeat Lucifer. Again. And that she’s the only person in this universe or any universe that can defeat him.