The film follows Dr. Bill Harford (Tom Cruise), a successful New York City doctor, whose life appears perfect on the surface. However, his world is turned upside down when his wife, Alice (Nicole Kidman), confesses to having a fantasy about being with another man. This admission sets off a chain of events that takes Bill on a journey of self-discovery, as he becomes increasingly obsessed with uncovering the truth about his wife's desires and his own.