In Leningrad there are sisters - Nadia and Lida Ryazayev. They were left without parents early and grew up in an orphanage. Now Nadia works at a construction site and is studying at a technical school. Lida is a schoolgirl.
Arriving once home, Nadia catches up with Lida her friend at the school of Cyril. They argue about happiness. Lida believes that happiness is in labor when you work not for yourself, but for others. However, when Cyril asks her if she herself is happy, Lida answers “no.” Comes uncle Ryazayev - Ukhov. He believes that the philosophizing of Cyril about life is "artisanal." Cyril argues with him and eventually leaves.
Suddenly, a certain Ogorodnikov appears. He was called to the party committee and accused of persecuting Nadia with his courtship. Nadia explains that she was just fantasizing, telling friends about him. Ogorodnikov demands that she explain this to his wife. He dials the phone number and hands the phone to Nadia. Nadia listens to everything and admits that she was joking. Ogorodnikov leaves without saying goodbye. Ukhov, angry at Nadi's trick, leaves behind.
Left alone, the girls begin to read aloud "War and Peace." Lida is finishing school and is about to enter the theater school at Nadine’s will. She is scared that she will not succeed, but Nadia is sure that her sister has great talent. A theater patronized their orphanage, they were often taken to performances, and she forever remembered how Lida’s eyes were burning then. Now she helps her sister prepare a monologue and, with all her soul, wants her to pass the selection.
The action is transferred to the theater school, where exams are held. Lida is worried that she knows nothing and does not remember. Nadia almost pushes her into the office, where the commission accepts. When Lida leaves after some time, it is clear that she did not pass. Nadia does not believe her. She goes to talk to the commission herself, in which the director Vladimirov sits, with whom Nadia was once familiar. Vladimirov recalls her and demands that she read the monologue. Nadia does not listen to him and persuades her to accept her sister. Vladimirov stands his ground. Then Nadia reads the only thing that she remembers by heart - an excerpt from an article about the theater.
Returning home, where they are already waiting for Ukhov, the girls say that Nadia passed the selection, but Lida did not. Uncle persuades Nadia not to quit college and work, says that this is a profession, and you can do theater at your leisure, that artists have almost always difficult times, no roles, no plays, nothing, asks Nadia to think about her sister for one they cannot live on a scholarship. Nadia agrees: unfortunately, he is right.
It takes two years. Lida lies in bed, she is sick: the consequences of a ski trip organized by Cyril. Cyril, who came to visit her, listens to numerous reproaches of the sisters. Comes Ukhov. He expels Cyril so that he no longer dares to approach Lida. Lida tries to catch up with him, but Ukhov forcibly puts her back to bed. The doorbell is ringing. Ukhov leads a shy man of about thirty. This is Vladimir Lvovich, with whom Ukhov wanted to introduce Nadya, hoping that marriage could grow out of this acquaintance. Vladimir asks Nadia to tell about himself, but she doesn’t want to. She directly tells Vladimir that he had better leave. The indignant Ear also leaves. Nadia apologizes to Lida that she allowed to expel Cyril, however, she believes that it will be better. She says that she wants only happiness for Lida, recalls their childhood and does not believe that none of this can be returned.
Two more years pass by. Cyril and Lida meet again, only Cyril is now married. He hides his relationship with Lida from his wife. For Cyril, this situation is disgusting. He hates lies, but systematically lies to his wife. But he cannot lose everything that connects him with Lida. Lida doubts whether this is love, but Cyril does not blame anything.
Ukhov asks Nadia not to let Cyril into the house, Nadia does not listen to him. She went to the theater and asked herself a small role: she doesn’t care what - if only they would give something. Vladimirov tells her that she has lost her personality.
Suddenly, Cyril's wife, Shura, comes. She is looking for a husband, because she was offered tickets for the concert. She is a teacher, she has a cheerful character, she is a very good person. Cyril and Lida come. Nadia promises the outgoing Shura that Cyril will no longer come here.
Lida tells her sister that she will not live the way she wants, accuses her sister of having driven Kirill away, she says that common sense does not bring happiness. Nadia punches Lida in the face with anger, then says that she is guilty and has no right to demand anything from them with Cyril. She notices that she has all the words and thoughts, like Ukhov. Lida is about to leave. Nadia is trying to keep her, but she still leaves.
Nadia collapsed onto the bed, shakes her head and repeats only one thing: “What should I do?”
