Playboy Mark Rutland realises Marnie is a kleptomaniac who specialises in stealing from her employers. He blackmails her into marriage, intent on curing her frigidity and criminal nature.
Alfred Hitchcock intended Marnie as a vehicle for Grace Kelly, but wound up casting Tippi Hedren, his discovery of The Birds.
The glacial Kelly might have made an interesting Marnie -- Hitch was obviously turned on by the idea of having the Princess raped by James Bond -- but Hedren gives the performance of her career, playing an uncomfortable visit to a mother who dotes on a Marnie-substitute little girl but is nervous of her real daughter ('Why don't you love me, Mama?') and the traumatic mercy-killing of her injured horse with such brilliance it's an injustice she wasn't even nominated for the Best Actress Oscar that went that year to Julie Andrews as Mary Poppins.
The first act is a cool study of a professional serial thief who juggles identities and hair colours as she takes jobs in a series of conservative firms and wins enough trust to walk away with substantial sums of money, allowing for a Hitch set-piece robbery complicated by a hard-of-hearing cleaning lady.
The second half is a strange crossbreed of sadistic love story and psychological drama. 'One might call Marnie a sex mystery, that is if you used such terms,' claims Hitch in his typically deceptive trailer.
Sean Connery finally got to show that he was more than 007 as the publisher-playboy with an interest in taming dangerous animals who tries, for his own perverse motives, to get to the bottom of the childhood trauma that has made Marnie frigid (a semi-rape honeymoon experience doesn't help), terrified of thunderstorms, a compulsive shapeshifter and thief and a nervous wreck at the sight of the colour red.
This remains a compelling Hitchcock thriller but it's Tippi Hedron's remarkable central performance which steals the show.