Separate, they are nothing. Together, they are a secret worth killing for. Ari Keir has always felt hollow. An empty longing has lived inside her chest for as long as she can remember. And for nearly eighteen years, she never knew what caused it. Cai Balere does not know why his heart is defective. Never has it held a full beat. Just as if half of it had vanished; dead to him and the world. A lie told from birth transformed them from siblings into strangers. Kept secreted away by his powerful, political mother, Cai broke all of her rules to release a photograph of himself, as well as a promise. On his eighteenth birthday, January 1, 2358, he would return to the city of his birth, Valor, America. His goal was to host the most memorable party Valor had ever seen. Given the freedom of a neglected teenager, Ari Keir knew a thing or two about taking care of herself and trusting few. When a single picture makes her go weak in the knees, however, she reaches out to her best friend for help. The idea is insane and impossible to believe, but as Ari locks eyes with Cai's photograph, she knows in her bones that she is no longer alone. The orphan has a family after all. From the moment Ari learns of Cai Balere, someone is out for blood. Running from all she has ever known, the scrawny teenager finds herself greeting her future far sooner than expected. To save herself and Cai, however, she will do whatever it takes. Against all odds, Ari and Cai are brought together, because they never should have been torn apart. Desperate as they were to reach each other, they're even more determined to keep one another. Separate, they are vulnerable. Together, they are invincible.