Being deemed worthy means magic and a lifetime underground. Being deemed unworthy means death. In the underground city of the Burrows, every eighteen-year-old must undergo the a sacred ceremony where ancient, magical creatures called Auryths decide who is worthy of power and who is not. Lennon Benfield has dreaded this day her entire life. If chosen, she'll wield magic, gain protection, and secure her future. If rejected, she'll be cast out and exiled above ground where the air is poison and survival is impossible. At least, that's what the Regime wants them to believe. Slade Whitlow knows better. Exiled years ago, he's learned the truth about the world above, and about the ones who condemned him. Now, he leads those the Regime sent to die, protecting them from the dangers on the surface and the lies that drove them there. Lennon has always believed every life is worthy. Slade has seen what happens when that belief gets people killed. But as buried secrets rise and impossible choices close in, what they fear most won't come from the world around them, but from the people they're becoming. Because their greatest threat may not be above or below, but within.