Looking to earn some easy cash, Jessica Farris agrees to be a test subject in a psychological study about ethics and morality. But as the study moves from the exam room to the real world, the line between what is real and what is one of Dr. Shields's experiments blurs. In this thriller by the authors of The Wife Between Us, Shields seems to know what Jess is thinking, and her behavior will be monitored and even manipulated. Caught in a web of attraction, deceit and jealousy, Jess quickly learns that some obsessions can be deadly.