Retired police detective John "Scottie" Ferguson suffers from acrophobia and vertigo following an incident in the line of duty that led to a police officer's death. His old college acquaintance, Gavin Elster, asks him to follow his wife, Madeleine, claiming she has become possessed by the spirit of her ancestor, Carlotta Valdes, who committed suicide. Elster expresses concerns for Madeleine's well-being and mental stability. Scottie is hesitant but takes the job, tracking her movements across San Francisco. As he observes her behavior, which includes visits to Carlotta's grave and a portrait of her at a museum, Scottie becomes increasingly intrigued by Madeleine. Despite his condition, he manages to rescue her when she jumps into the bay, leading to a complex relationship developing between them.

Throughout the surveillance, Scottie notices Madeleine's peculiar fascination with the Golden Gate Bridge, where Carlotta had leaped to her death a century earlier. He finds himself falling deeply in love with her, despite the unusual circumstances of their acquaintance. As Scottie's feelings intensify, he becomes more and more entangled in the web of mystery surrounding Madeleine's life and supposed ancestral possession. The engagement leads him through a dizzying array of emotional highs and lows, amplifying his feelings of vertigo both literally and figuratively as he struggles to understand what's truly happening with Madeleine and her strange connection to the past.