Vronsky continues life as usual in his regiment. Though he never lets slip that he loves Anna, the whole of St. Petersburg high society knows about his feelings for her. The women who once praised Anna as righteous now wait for a chance to sling mud in her face.
Vronsky hears about an upcoming officers’ steeplechase, so he buys a new mare, named Frou-Frou, to ride in one of the races. On the day of the races, Vronsky visits Frou-Frou in the stable, and she grows more agitated as he approaches. Vronsky reflects on everyone pestering him about Anna.
Just before the horse race, Vronsky visits Anna at her nearby summer house. She has been thinking about him and seems somewhat distraught. Her son, Seryozha, is absent, as Vronsky had hoped. Anna informs Vronsky that she is pregnant. He urges her to leave her husband and live with him instead. Vronsky cannot imagine how Anna can wish to continue living in such deceit, not realizing that the reason is her love for her son. Suddenly, Vronsky realizes he is late for the races.
Vronsky arrives at the racetrack just as Frou-Frou is being led out of the stable. Vronsky’s brother, Alexander, approaches him and tells him to answer a letter their mother has recently sent. Vronsky is expected to do well in the race, as his only serious rival is another officer, Makhotin, who rides a horse named Gladiator. Nonetheless, Vronsky is agitated. The race begins. After a slow start, Frou-Frou outpaces all the horses except Gladiator. At last, Frou-Frou pulls ahead of Gladiator, and is in the lead. Vronsky is ecstatic. But during a jump over a ditch, he shifts in the saddle incorrectly, causing Frou-Frou to fall. The horse breaks her back and must be shot.
Meanwhile, the Karenins’ relationship, on the surface, has remains just the same as before. Unable to face or admit his own feelings for his wife, Karenin treats Anna with an offended hostility. He hardly ever sees her, as she goes away for the summer, living near Betsy Tverskoy’s home in the countryside. At the officers’ steeplechase, which Anna and Betsy attend together, Karenin observes that his wife only has eyes for Vronsky. When Vronsky falls, Anna weeps with alarm, and then with relief after hearing that he is safe. Karenin offers to take Anna home, but she prefers to stay. Karenin tells Anna that her visible grief upon Vronsky’s fall is highly improper. Finally, on the carriage ride home, Anna frankly confesses to Karenin that she loves Vronsky and hates Karenin. The shocked Karenin demands that she continue to observe the outward conventions of marriage for appearances’ sake until a suitable solution is found.
Meanwhile, Kitty and some of her family are at a spa in Germany. The Shcherbatskys enjoy socializing with European aristocrats as they await an improvement in Kitty’s health. One of the spa guests is a snobby, elderly, Russian invalid named Madame Stahl, who is famously devout and is accompanied by a young girl named Varenka. Kitty likes Varenka immensely but is nervous about meeting her. Kitty’s mother learns that two spa guests, a tattered Russian gentleman and his female companion, are in fact Levin’s brother Nikolai and Nikolai’s girlfriend. One day, Kitty’s mother is so impressed with Varenka that she allows Kitty to meet the girl. Kitty is delighted, and both mother and daughter are enchanted by Varenka’s goodness.