Stefan and Dolly Oblonsky have had a little spat and Stefan has asked his sister, Anna Karenina, to come down to Moscow to help mend the rift. Anna's companion on the train from St. Petersburg is Countess Vronsky who is met at the Moscow station by her son. Col. Vronsky looks very dashing in his uniform and it's love at first sight when he looks at Anna and their eyes meet. Back in St. Petersburg they keep running into each other at parties. Since she has a husband and small son, they must be very discreet if they are going to see each other alone.
Source : IMDb