Forbidden by Judy Waite
Published by OUP 

This is a strange unusual story of a girl, Elinor, who has been brought up in a cult.  For as long as she can remember, she has been one of the Chosen and, when she turns 16, it is her destiny to be bonded with the cult leader.  But a chance encounter with a stranger starts her to question her emotions and beliefs.  Does she have the will to break free and can she escape her fate?