A woman's face gives way to a kaleidoscope of credits, signalling the start of Alfred Hitchcock's Vertigo to Bernard Hermanns haunting score.
A criminal climbs up the rungs of the ladder on a dark San Francisco night. John "Scottie" Ferguson (James Stewart), a detective, and a police officer are hot on his trail. They chase him across the top of buildings. The thief jumps between two buildings, making it across. The police officer follows, but Scottie cant get his footing. He slips. Scottie hangs on to the gutter as his fear of heights kicks in. The police officer tries to grab his hand, but he falls to his death. Scottie witnesses this and clutches to the gutter.
Months after the incident, Scottie reclines in the home of Marjorie Midge Wood (Barbara Bel Geddes), a painter and underwear designer. She is concerned about Scottie's plans now that he is back in shape. He has quit the police force due to his acrophobia, and does not want to be a desk jockey. Midge and Scottie used to be engaged back in college (Midge had called it off). She urges him to take a vacation. "Don't be so motherly", responds Scottie. They discuss an old college buddy, Gavin Elster (Tom Helmore), who wants to meet with Scottie. Before Scottie prepares to meet Elster, he explains his plan to get over his fear. He first stands on a step stool. Midge gives him a ladder chair, and Scottie is able to handle the first two steps, but when he reaches the top, he looks out the window and panics. He collapses in her arms.
A familiar pedestrian crosses the street near the docks. Scottie meets Gavin who is in the shipping business. Gavin had married into the successful shipping business, and he wants Scottie to tail his wife. He does not suspect infidelity, but has suspicions that his wife has been possessed by something. Her words would fade, and she would become distant. She wanders, and even moves differently. Scottie initially thinks he is crazy, but is intrigued. Gavin tells him to meet them at Ernie's Restaurant the following night.
Ernie's Restaurant is a lavish, upscale eatery, plush and scarlet. Scottie first spots Madeleine Elster (Kim Novak) who is stunning, with platinum blonde hair and a green shawl. He is mesmerized by her.
The next morning, he stalks her outside of her house. She wears a simple gray suit with white gloves, as she gets into her green automobile. Scottie trails her through the streets of San Francisco, as she visits a flower shop and purchases a small bouquet. He then trails her to the Mission Dolores, where she goes through the chapel to the cemetery, where she stands at a grave. As she exits, Scottie notes the headstone, which reads "Carlotta Valdes born: December 3 1831 died: March 5 1857". He then follows her to the Palace of the Legions of Honour, an art museum. Madeleine sits, staring at the painting for hours. Scottie notices that the bouquet she had purchased is just like the one in the drawing. Also, her hair is done exactly like the woman in the painting. Scottie discovers from the curator, that the painting is titled "A Portrait of Carlotta". Finally, he follows her to the McKittrick Hotel, where Scottie observes Madeleine on the second story. Scottie enters the hotel, which has a very baroque look to it. Scottie asks the manager of the McKittrick Hotel (Ellen Corby), who is the occupant of the room. She hesitates to tell him, until Scottie reveals his badge. The manager then notes that she has not been in the room all day. Scottie finds this impossible, and goes up to her room. He looks down the street to discover that her car is gone.
Scottie returns to Midges home where she tells him of San Francisco historian Pop Liebel (Konstantin Shayne), who owns the Argosy Book Shop. Pop tells Scottie that a rich man built the house for Carlotta Valdes, and they had a child. However, the rich man threw Carlotta out, and took her child. Carlotta went from depressed to insane, and took her own life.
On the drive home, Midge and Scotty talk about the portrait; he shows her the catalogue picture. The resemblance is uncanny. Another conversation with Gavin reveals that Madeleine had started to wear Carlottas jewellery, particularly a ruby pendant found in the painting. Madeleines great-grandmother was Carlotta Valdes, a fact that Madeleine does not know. Gavin only knows this fact, because Madeleine's mother told him.
Scottie follows Madeleine the next day to the Palace of the Legions, where she watches the portrait. Then he follows her to Fort Point near the Golden Gate Bridge. Madeleine strolls by the shore, throwing petals into the bay, until she jumps in. Scottie dives after her. He tries to revive her, but she is out cold, and he takes her back to his apartment.
She wakes up naked in his bed, where she is handed a red bathrobe. He asks her if she remembers anything, and explains that he rescued her from drowning. Madeleine maintains that she fainted and fell. He questions her, "Has this ever happened to you before?" He gets a telephone call from Gavin, concerned about the whereabouts of his wife. Scottie reassures him that Madeleine is at his apartment. Gavin confides that Madeleine is twenty-six - the same age in which Carlotta Valdes committed suicide. Scottie hears the door close, and realizes that Madeleine has left. As Madeleine drives away from Scottie's house, Midge arrives just in time to have a misunderstanding. She believes that Scottie and Madeleine are in a relationship.
The next morning, Scottie trails Madeleine through the streets of San Francisco, only to find that Madeleine has been looking for Scottie's house. Scottie catches her leaving a thank you letter for saving her. She did not know the address, but followed the Coit Tower. Scottie insists that they wander together, because they are both alone.
They arrive at Big Basin Redwoods State Park, where they admire the ancient redwoods. As they view a cross-section of a tree with the approximate dates of historical events. Madeleine goes into a trance, seemingly becoming Carlotta, recounting the dates of her birth and death. Madeleine wanders deeper into the woods, and Scottie follows her. He confronts her about the jump, and tries to bring Madeleine back. By the shore, Madeleine begins to reveal fragments of her vague memories: an empty grave with no name, waiting for her; an empty room in which she sits alone; and finally a tower, bell, and garden in Spain. Madeleine admits she is not crazy; she does not want to die. They kiss as the waves crash onto the rocks. Scottie promises he will never leave her.
Midge had sent a note to Scottie, who arrives at her house. Midge had been painting a picture of herself as Carlotta Valdes. Scottie is not amused. Distressed, he leaves her home. Midge ruins the painting, upset that she admitted she had fallen for him again.
Madeleine returns to Scottie's house, where she tells him of an awful dream, with a tower, a bell, and a village. As she describes the location in detail, Scottie finishes her descriptions. "You've been there!" he exclaims. Scottie is talking about the San Juan Bautista, a mission that has been converted into a museum. They drive to the mission.
When they arrive at the mission, they enter the livery stable, where Scottie tries to dismiss the dreams logically. He points out certain objects that are real. They kiss. Madeleine explains she must do something. She asks him if he believes she loves him. He replies yes. "And if you lose me, then you'll know I, I loved you. And I wanted to go on loving you'', she says. She starts to go to the church, when Scottie realizes she is going to the bell tower. Scottie chases her into the chapel, and sees her run up the stairs. He follows her, but as he looks down, his acrophobia sets in: he gets vertigo. He cannot follow her up to the top of the bell tower. He watches, helpless, in fear and horror as Madeleine's body plunges to the tiles below. Scottie staggers out of the mission, sun blinding his eyes, dumbfounded.
At the a judicial hearing concerning Madeleine's death, the judge is particularly cruel to Scottie, as he insults him for letting his weakness get in the way of saving Madeleine. The court rules the incident a suicide. Gavin comforts Scottie, while telling him that, with the loss of his wife, he can no longer stay in San Francisco. Gavin sets off to Europe.
Scottie has trouble sleeping. Blue and purple flashes signal his nightmare, as an animated bouquet unravels. He hallucinates of Carlotta Valdes at the hearing, with special emphasis on the ruby necklace. Scottie walks into the cemetery where there is an open grave. Scottie falls into a tunnel, then his body lands next to Madeleine's on the tiles of the mission. He wakes up in a cold sweat.
Midge arrives to care for Scottie in a psychiatric ward. She tries to comfort him, "mother's here". Scottie will not speak, he is in a daze. The doctor believes that Scottie will be incapacitated for a year due to stress and anxiety from his depression and guilt.
When Scottie gets out of the hospital, he visits the old Elster home, and spots the green car. In the distance, a woman in gray suit is getting in it. Unfortunately for him, it is not Madeleine; it is an old neighbour who bought the car from Gavin. At Ernie's he spots a woman in grey, but again, it is not Madeleine. He even sees Madeleine at the Palace of the Legions, but once again, it is not her. While looking at a bouquet at a flower shop, he sees a striking brunette in a green suit. Although she doesnt resemble Madeleine in dress, style, or movement, the face is a dead ringer. He follows her to the Hotel Empire, and sees her through the fifth floor window.
When Scottie knocks on the door, the woman is concerned that he is a creep. He reassures her he just wants to talk. He spits questions at her, and she reveals that she is Judy Barton (Kim Novak again) from Salina, Kansas. Judy realises that Scottie's heart is broken for his former flame, and she takes pity on him. She agrees to go for dinner with him at Ernie's.
Scottie leaves and Judy tells her story via flashback. She WAS Madeleine, running up the steps of the bell tower. At the top, Gavin Elster was there, holding the body of the REAL Madeleine Elster, dressed in exactly the same wardrobe as Judy. It was the real Madeleine's body that was thrown off the bell tower, with Judy letting out the scream. Judy reveals the gray suit that she wore as her disguise, hidden in the back of her closet. She begins to write a letter to Scottie, explaining that she was Gavin's accomplice in the murder of his wife. She had become her doppelganger to fool Scottie, and use him as a witness to explain that Madeleine was mentally unstable. Gavin had known about his vertigo, and knew that Scottie would never make it to the top of the bell tower. Judy reconsiders this letter, and tears it up.
That night, Scottie suspects he sees Madeleine at Ernie's. He escorts Judy home that night, her apartment flooded with the green neon light of the Hotel Empire sign. Although he loves Madeleine, there is something about Judy that he can't shake. They agree to meet the next morning.
They engage in a series of dates, with Scottie becoming happier with the relationship. However, he begins to buy her clothes, searching obsessively for the gray suit and white gloves that Madeleine used to wear. As Judy begins to break down, Scottie also realizes that she must dye her brown hair, platinum blonde. Although Judy begs him to love Judy Barton, she has fallen so in love with him that she will conform to his image.
Her makeover complete, she returns to a waiting Scottie who has her pull her hair back for the final transformation. In a dreamlike state, with the green glow all around them, they embrace and kiss. The room turns into the livery stable from the Mission, Scottie's last kiss with Madeleine, and then back to the apartment.
A couple nights later, the two decide to go out to Ernie's. Judy dresses up, and wears the ruby pendant. Scottie realizes that something is amiss. He suddenly becomes distant. He passes Ernie's and continues driving past the Redwood trees. He tells her he has one final thing to do. They arrive at the mission, where Scottie forces Judy to re-enact Madeleine's death. He wants to use this as a second chance to save Madeleine and exorcise his demons forever.
As he reaches the top of the bell tower, conquering his acrophobia, he puts the whole puzzle together. He realizes that Judy was the counterfeit all along. He never knew Madeleine. He was being set up as Gavin Elster's witness in the murder of Elster's wife. He pulls Judy to the top of the tower, where she protests. Judy pleads that she had fallen in love with Scottie. They kiss. The sudden appearance of a nun, however, shocks Judy, who plummets to her death off the ledge. A stunned Scottie is distraught, losing the same woman twice in the same fashion.