In the prologue the year is 1349 and Seraphina is fourteen years old, dancing the night away with a masked stranger. She heads outside for some fresh air, where the masked stranger reveals himself to be the alchemist's son, Cyrus. He says he has always noticed Seraphina. Then out of nowhere, a man and a woman come to rob them. The woman stabs Seraphina in the back and she is about to die. Cyrus uses his father's immortality elixir to separate the cord of Seraphina's soul from her body and put her soul into the woman who stabbed her's body. Seraphina wakes up in the other woman's body and she runs off to spend the rest of eternity with Cyrus. 
 It starts off feeling like it will be a beautiful love story, but fast forward about 650 years to present day and Cyrus is now a psycho. The way the immortality elixir works is that the soul has to over take another body about every ten years. So over Seraphina's lifetime she has killed about 65 people in order to survive. The soul can transfer into a damaged body and it will heal the body but the soul sucks the body dry of energy over the course of ten years. Seraphina tries to choose bodies that belong to people that are self destructive and don't want to live but she can't do it anymore. She doesn't want to be responsible for another death. Except Cyrus refuses to let her go. He has become controlling, manipulative, and heartless. Seraphina comes up with a plan to escape Cyrus and allow her current body to wear out and die. 
 When Seraphina does finally escape Cyrus she ends up finding a car accident victim and tries to give her CPR. The need to survive overtakes her and she accidentally transfers her soul into the car accident victim's body. She ends up taking over her Kailey's life, attending her school, falling for her the boy next door, enjoying her friends and family. She normally just gets a new identity but Cyrus never taught her how to do that or how to survive on her own. She lucked out with all the technology the world now has to offer because she uses facebook, google, photo albums, and all the clues around the girls room to try to blend into her life. But Seraphina is afraid Cyrus will catch up with her. He is smart and knows her well and if he finds out about the car accident he might come to take her away from the new life and people she loves. 
 I read the book all in one night and it held my attention well. The immortality concept was unique and original. The soul having to travel to a new body was an interesting twist. It was a bit short and I did want a little more development. I loved Noah but I was hoping for a little more between them. It seemed like he had always been into Kailey but when Seraphina took over her body he seemed to all of a sudden really fall for her but I didn't totally feel it. I definitely saw why Seraphina would fall for Noah though. His character was sweet and considerate. I also didn't really fully understand why Cyrus was so obsessed with Seraphina other than he was just a psycho. They apparently loved each other at one time but at the beginning of the book they didn't seem like a couple. It felt like they were already broken up so I guess he just liked to control her. I would think he would just assume she died but he goes to a lot of trouble to try to track her down. There was a big cliffhanger so I definitely need to see what happens next. 
 Dear Cyrus, 
 I loved you once, with all my heart, and I stayed alive, in one form or another, for centuries because I could not bear to be apart from you. But the years have changed us, and not for the better. Every death we've caused has killed our love, bit by bit. I cannot kill another human in order to live. When my current body is lost, I will be too. 
 Until the next life, 
 Seraphina