Anna Karenina (Vivien Leigh) is married to Alexei Karenin (Ralph Richardson), a cold government official in St Petersburg who is apparently more interested in his career than in satisfying the emotional needs of his wife. Called to Moscow by her brother Stepan Oblonsky (Hugh Dempster), a reprobate who has been unfaithful to his trusting wife Dolly (Mary Kerridge) once too often, Anna meets Countess Vronsky (Helen Haye) on the night train. They discuss their sons, with the Countess showing Anna a picture of her son Count Vronsky (Kieron Moore), a cavalry officer.
Vronsky shows up at the train to meet his mother, and is instantly infatuated with Anna. He boldly makes his interest known to her, which Anna demurely pushes away – but not emphatically so. At a grand ball, Vronsky continues to pursue the married Anna, much to the delight of the gossiping spectators. But poor Kitty Shcherbatsky (Sally Ann Howes), Dolly’s sister who is smitten with Vronsky, is humiliated by his behaviour and leaves the ball – much to the distress of Konstantin Levin (Niall MacGinnis), a suitor of Kitty’s who was rejected by her in favour of Vronsky. However, after a change of heart, Kitty marries Levin.
Boldly following Anna back to St Petersburg, Vronsky makes it known to society that he is the companion of Anna – a notion she does nothing to stop. Soon, society is whispering about the affair, and it’s only a matter of time before Karenin learns of the relationship. Outwardly more worried about his social and political position than his wife’s passion, he orders her to break off with Vronsky or risk losing her son. She tries, but cannot tear herself away from Vronsky.
Leaving Karenin, Anna becomes pregnant with Vronsky’s child. Almost dying in childbirth (the child is stillborn), Anna begs Karenin for forgiveness, which he coldly grants. Karenin, being magnanimous, allows Vronsky the notion that he may visit Anna if she calls for him. Embarrassed by the scandal, Vronsky tries to shoot himself, but fails.
Anna tries again to live with Karenin, but cannot get Vronsky out of her head. She leaves Karenin for good, abandoning her child to live in Italy with Vronsky. But her doubts over Vronsky’s feelings for her grow, and she eventually pushes him away. Realizing that she has lost everything, Anna walks onto the railway tracks and commits suicide by letting the train hit her.