What would you do for one thousand dollars? For five thousand? Damaged by love and determined not to be hurt again, Zoe Alexander receives an invitation to take part in a bizarre behavioral experiment conducted by a handsome and mysterious millionaire known only as The Doctor. Though it's the pay that first attracts her to his private laboratory, she's soon deeply involved in a situation that challenges her very idea of who she is and what she's capable of. Zoe finds that the experiment changes her life in ways she'd never imagined, transforming her into a woman of intense passion and transcendent love. She becomes obsessed with only one thing-the one thing she can never be told-the shocking purpose of The Experiment itself.