Twenty-five-year-old Valentine, a high school teacher, wakes up one morning with a sense of happiness, because he dreamed of a rainbow. Valentine is late for work – he teaches French in high school. He thinks that lately he has become too often to lie, and understands: lying on trifles means that he is not free and someone is afraid. Valentine decides to live a day without lying.
Once he wanted to study at the Literary Institute at the department of artistic translation, then – to become an interpreter and go abroad. Neither one nor the other failed. As it was not possible after the end of the year to leave for the steppe, which he dreamed of, it was not possible because of his mother and Nina’s girlfriend. Now he translates stories from one language to another, although no one promises him money.
In the trolley bus, Valentine drops three kopecks into the cash register and tears off the ticket – because he is sorry to overpay a penny by dropping a piglet. Noticing the controller, he honestly talks about the reason for underpayment, and, surprised, she does not take a fine from him.
At school, he begins his usual lesson in the fifth “B” class. The pupil Sobakin, as always, climbed onto the Swedish wall, but Valentin does not require that he sit down at the desk. Instead of explaining the boring grammar to the children, Valentin tells them about the artistic translation, recites “Cola Bryunion” in translation of Lozinsky and Rabelais in Lyubimov’s translation. The children listen to Rabelais for the first time in their lives, and Valentine sees that for the first time they do not look through him. He does not try to justify himself before the head teacher Vera Petrovna for being late, and she says that it’s impossible to talk to him today.
Coming out of school, Valentine without a queue buys grapes, because he hurries to Nina, with whom he quarreled yesterday; the queue silently allows him to do it. Valentin does not know if he loves Nina, who has... known him for five years, but he has the feeling that God himself instructed him to take care of her. But to deceive Nina, confessing love, he does not want this day. At dinner, Ninin’s mother, who regards Valentine as a strange person, asks if the soup is delicious – and he can not respond diplomatically. Father retells the story read in Pravda, about how the eagles attacked the plane. One eagle punched his chest, and two flew away. Valentine thinks: would he have rushed to the plane with his chest or would have flown away? Ninin’s mother believes that only the last fool can rush to the plane. Finally Valentine confesses to Ninin’s parents what awaits when they leave. .. Upon hearing this, the mother declares that he “vypryuchivaetsya.” Valentine is surprised at himself: all day he tried to be what he is, but nobody took him seriously. The controller thought that he was acting out for her, the head teacher – that flirting, Nina – that he was keen, and her mother – that “vypryuchivaetsya.” Only the children understood it correctly. He lived the day as he wanted, feared no one and lied in small things, because if you lie in small things, then by inertia you will lie in the main thing. But Valentine realizes that it is impossible to repeat such a day tomorrow, because you can tell the truth only if you live in truth. “Otherwise – or lie, or put the phone down.” He also hangs up to not offend Nina, when his friend, Lyonka, who called him on Ninin’s number, informs that Valentina is waiting for a woman. Once Lyonka left after the institute for the steppe, and Valentine did not leave – only wanted. On a day without lying, Valentine realizes that in a few years he will turn into a loser, a man “who wanted to.” Asked by Nina what he is going to do tomorrow, he answers: “Breaking your whole life.” Nina thinks that tomorrow he is going to make her an offer…