At the end of the Second World War, Iya Sergeyevna, Viktoriya Miroshnichenko as a tall nurse nicknamed Beanpole (Дылда), works in a Leningrad hospital under Dr. Nikolai Ivanovich Andrey Bykov. Iya sometimes suffers fits where she is temporarily immobile, just slightly trembling. She lives in a communal apartment with the three-year-old boy Pashka Timofey Glazkov.
One day, Iya accidentally smothers the child to death while suffering an episode. Days later, Masha arrives at Iya's room, returning in uniform from the front, and asks where her son Pashka is.
Bitter about his death, yet seemingly unfazed, Masha invites Iya out dancing. They accept the invitation to go with Sasha Igor Shirokov and his friend in their car. Masha orders Iya out of the car to go on a "walk" with Sasha's friend so Masha can have sex with the very bashful Sasha. Iya attacks Sasha's friend when he attempts to seduce her, and beats Sasha over the head when she finds him having sex with Masha. The next day while at a communal bath, Iya notices Masha's abdominal scar, and Masha tells her that she wants to have a child to heal herself.
Masha begins work at the hospital, telling Dr. Ivanovich that she and Iya served together in an anti-aircraft gun crew, but Iya was discharged after suffering a traumatic head injury, while Masha continued serving in the army. Shortly afterwards, the wife of Stepan Konstantin Balakirev, a paralyzed soldier, arrives at the hospital to find her husband alive, despite having already told her children that he was killed at war. Stepan cannot bear the idea of returning to his children as a quadriplegic. Alongside his wife, they beg Nikolai Ivanovich to euthanize him. Nikolai is at first extremely opposed to the idea, but eventually relents, asking Iya to do the task and indicating it will be the "last time". Iya hesitantly agrees and during one night injects Stepan.
Masha, on night watch and lying down due to fatigue due to the war, watches Iya and Stepan. Afterward Dr. Ivanovich examines Masha and confirms her infertility.
Masha asks Iya to bear a child that would be Masha's. When Iya vehemently refuses, Masha reminds her that she "owes" her a child after she let Pashka die in her care. At a party, Masha asks Dr. Ivanovich to impregnate Iya; he refuses, but she blackmails him, threatening to make public the euthanasia. Masha says she doesn't care if Iya is also exposed. Later in their room, Iya insists Masha lie against her in bed, while the doctor penetrates Iya, who cries and is distraught.
Masha continues to see Sasha afterwards, frustrating Iya, who is confused and jealous. Iya finds out she is not pregnant. While trying on a dress for their seamstress neighbor, Masha twirls frantically and frenetically over and over and over. Iya calms Masha by kissing her. Masha initially fights her off but Iya suffers episode, during which Masha kisses her strongly in return.
Later, after an argument in which Iya orders Sasha to stop coming to their apartment with food, Sasha invites Masha to meet his parents. Iya walks to Dr. Ivanovich's house and tearfully asks him to impregnate her. He declines, but invites her to come with him and leave the city tomorrow.
Masha visits Sasha's parents at their large, posh estate, where Sasha introduces her as his girlfriend, soon to be wife, but Masha receives a very cold response. The mother judges Masha for having served as an "army base wife" (Походно-полевая жена). Masha "reveals" that her abdominal scar was not caused by a combat shrapnel injury as she had earlier described to the doctor, but by many abortions. Her comment is a stereotype of what civilians think about fighting women during the war — not respecting those women's sacrifice and heroism. She says what those people could believe in, instead of the truth. She asserts that Sasha loves her, and they will have a child, given to them from her friend. The mother warns Masha that Sasha would become bored with her and discard her. Sasha, enraged, storms out of the room, and Masha rides the tram home alone.
On the way home, Masha's tram hits a tall woman. Masha is unable to recognize the woman dead underneath the tram, and runs home to find Iya having an episode. Iya reveals she is not actually pregnant. Masha begins hitting her, but stops. Masha promises Iya that Sasha won't be coming around any more, and that they will be together from now on, will have a good life and raise a healthy child together, who will resemble both mothers, and will cure them from all pain they have carried until now. The two weep together in an embrace.
