Since her parents were killed, Vivienne has always felt ungrounded, shuffled through the foster care system. Just when liberation finally seems possible - days before her 18th birthday - Vivienne is hospitalized with symptoms no one can explain. The doctors may be puzzled, but Deacon, her mysterious new friend, claims she has an active Nevergene. His far-fetched diagnosis comes with a warning: She is about to become an involuntary test subject for Humanitarian Organization for Order and Knowledge - or H.O.O.K.