Seraphai never wanted to lead the next terrifying experiment, but refusing isn't an option. With powerful eyes watching her every move, she must keep herself-and her people-safe. She communicates with Cypher, a girl living in the city, through code in order to avoid being detected. Together, they plot an escape, needing to protect themselves without anyone catching on. But the deeper they go, the more dangerous the game becomes. Lies pile up. Friendships crack. And somewhere in the shadows, a murderer lurks-someone who knows exactly what they're up to. Seraphai and Cypher thought their trust in one another was enough. They were wrong.