It's Clara who's desperate to enter the labyrinth and it's Clara who's bright, strong and fearless enough to take on any challenge. It's no surprise when she's chosen. But so is the girl who has always lived in her shadow. Together they enter. Within minutes, they are torn apart forever. Now the girl who has never left the city walls must fight to survive in a living nightmare, where one false turn with who to trust means a certain dead end.