In a near future where a race of parasitic alien souls has quietly conquered humanity by inhabiting human bodies, a soul called Wanderer is implanted into captured rebel Melanie Stryder to extract the location of the last free holdouts. But Melanie's consciousness refuses to fade, and the two minds share one body, forging an uneasy alliance that turns Wanderer against her own kind. Fleeing to a hidden desert colony, she must win the trust of suspicious survivors. Andrew Niccol adapts Stephenie Meyer's novel into a glossy science-fiction romance, trading spectacle for an interior tug-of-war between two souls learning to coexist.