Leo Vasquez ends the end of his summer by beginning his senior year of high school with optimism and the party of the year. The only problem? Rayna Belvoir is out for blood and he's no longer sure if it's his or the other monsters chasing them both. With a dark family secret and a new world revealed, Leo and his twin brother Theo find that nothing is what it seems and they could very well lose those closest to them if they don't figure out who the real enemy is and quickly. Time is ticking . . .