Abhuman

She had a secret. She's on the run. She's being hunted.
In the Covenant, an insidious theocracy, genetic mutation carries a death sentence. Conform or die. It seems to be a perfect, harmonious society-but is it?
When sixteen-year-old Cheska Bellamy's mutation is exposed, she's forced to flee her starship to the partly-terraformed planet below. As she makes her way across a devastated landscape, she discovers that there had been a race of sentient creatures with a flourishing civilization. All that remain are battered ruins and a handful of Indigens who'd moved underground after Cheska's people began terraforming their planet.
When she connects with the human resistance on the planet, she learns that her people on the starship have been secretly enslaved by an alien race; the most terrifying part (for her) is that she might be the key to her people's freedom.