Thunderstorms are rolling across the summer sky. Every time one breaks, Rose Bowan loses consciousness and has vivid, realistic dreams about being in another woman's body. Is Rose merely dreaming? Or is she, in fact, inhabiting a stranger? Disturbed yet entranced, she sets out to discover what is happening to her, leaving the cocoon of her family's small repertory cinema for the larger, upended world of someone wildly different from herself. Meanwhile her mother is in the early stages of dementia, and has begun to speak for the first time in decades about another haunting presence: Rose's younger sister.