Seventeen-year-old Kaycee Reid is on the run. From her family, from her friends, from her secret society, from everyone and everything. For the past year, she has managed on her own, but the true reason for her leaving is catching up to her, and she needs to make a decision.

When her decision is made to find Lark, a recluse, and Thomas, his unreadable pupil, Kaycee learns that her world is much bigger than she could imagine. Darkness is on the horizon, and all their hope is left to a high school student who is unaware of his true nature. It is up to Kaycee to convince him to join their side. 

Kaycee thought leaving her society meant she run away from her accursed power, but she soon realizes she needs all her power to succeed, even if it means betraying anyone in her way.