An expert in animal behavior with a brilliant analytical mind, charismatic Oxford professor James Fieldhead needs a willing subject to test a groundbreaking device that may offer the key to understanding human emotions. Encouraged by Cara, his seductive new girlfriend, Ben Ashurst agrees to participate in the study, honored to be part of the first crucial stage of life-changing research. With a luxury resort on a pristine beach in Kenya as the site of the experiment, and Cara along for the ride, it seems a perfect way to spend the winter holiday. Yet beneath the surface of a sunny paradise awaits something cold and ruthless. As the experiment veers from abstract theory into terrifying reality, Ben finds there is no one he can confide in. Impetuous Cara is intimate one night, then distant the next, forcing Ben to wonder where her true allegiances lie.