Michelle Miller struggles with chronic sleepwalking. She and her husband, Dan, are attempting to conceive their first child following a miscarriage the previous year. During one of her sleepwalking episodes, Michelle ends up in the bedroom of her neighbor, Luke Williams, while his wife, Nancy, is away. They engage in a sexual encounter, of which Michelle remains oblivious, but Luke becomes infatuated with her and contemplates leaving Nancy. Michelle soon discovers she is pregnant, but is uncertain whether the father is Dan or Luke.