Twenty-five-year-old Valentin, a high school teacher, wakes up one morning with a feeling of happiness because he dreamed of a rainbow. Valentin is late for work - he teaches French in high school. He thinks that he has recently begun to lie too often, and he understands that lying to the smallest detail means that he is not free and is afraid of someone. Valentine decides to live a day without a lie.

Once he wanted to study at the Literary Institute in the department of literary translation, then - to become a translator and travel abroad. He failed either. How it was not possible at the end of the invasion to go to the steppe of which he dreamed, - it was not possible because of the mother and beloved girl Nina. Now he translates stories from one language to another, although no one promises him money.

In the trolley, Valentine drops three kopecks into the ticket office and opens the ticket - because he is sorry to overpay the kopeck by dropping a penny. Noticing the controller, he honestly talks about the reason for the underpayment, and, surprised, she does not charge him a fine.

At school, he begins the usual lesson in the fifth “B” grade. Pupil Sobakin, as always, climbed the Swedish wall, but Valentine does not require him to sit at his desk.Instead of explaining boring grammar to the children, Valentin tells them about literary translation, recites “Cola Brunion” translated by Lozinsky and Rabelais translated by Lyubimov. Children for the first time in their lives listen to Rabelais, and Valentine sees that for the first time they do not look through him. He is not trying to make excuses to the head teacher Vera Petrovna for being late, and she says that it is impossible to talk with him today.

After leaving school, Valentine out of turn buys grapes, because he is in a hurry to Nina, with whom he quarreled yesterday; the queue silently lets him do this. Valentine does not know whether she loves Nina, whom she has known for five years, but he has the feeling that the Lord God himself entrusted him with taking care of her. But he does not want to deceive Nina, confessing her love, that day. At dinner, Ninina's mother, who considers Valentine a strange person, asks if the soup is tasty, and he cannot answer diplomatically. Father retells the story read in Pravda, about how eagles attacked an airplane. One eagle broke its chest, and two flew away. Valentine wonders if he would throw himself on a plane with his chest or fly away. Ninina’s mother believes that only the last fool can throw a breast on a plane. Finally, Valentin confesses to Ninin’s parents that he is waiting for them to leave ... Upon hearing this, his mother declares that he is "getting out." Valentine wonders to himself: all day he tried to be what he is, but no one took him seriously. The controller thought that he was kidding her, the head teacher - that was flirting, Nina - that he was witty, and her mother - that was "getting out."Only the children understood him correctly. He lived the day as he wanted, was not afraid of anyone and didn’t lie in the details, because if you lie in the details, then by inertia you will lie in the main. But Valentine understands that it is impossible to repeat such a day tomorrow, because you can tell the truth only if you live the truth. “Otherwise, either lie or hang up.” He hangs up so as not to offend Nina, when his friend Lenka, who called him on Nina's number, reports that a woman is waiting for Valentina. Once Lenka left after the institute in the steppe, but Valentine did not leave - he just wanted to. On a day spent without lies, Valentine understands that in a few years he will turn into a loser, the person “who wanted”. When asked by Nina what he was going to do tomorrow, he replied: "Breaking his whole life." Nina thinks that tomorrow he is going to propose to her ...