A ten-year-old boy Petka was sent to teach to the barber Osip Abramovich. In a cheap hairdresser he brings water, the master and apprentices constantly shout at him and swear at him. His friend Nikolka is 13 years old, Nikolka knows a lot of bad words and often tells Petka obscene stories. The windows of the hairdresser salon go out onto the street, along which “indifferent, evil or loose” people walk, homeless people sleep on benches, drunks are fighting. Petya does not have holidays, all his days are similar to each other, his life seems to him a long unpleasant dream, he is increasingly losing weight, gets sick, his face appears wrinkles. Petka really wants to go somewhere else. When his mother visits, the cook Nadezhda, he constantly asks her to take him away from Osip Abramovich.
One day the owner lets Petka go to the dacha to the masters of Hope. On the train, the joyful Petka smiles at the passengers, asks how the train goes, smiles at the clouds. Outside the town of Petka, the eyes no longer seem drowsy, and the wrinkles disappear. Having become friends with the schoolboy Mitya, Petya pours a lot, fish, plays. However, at the end of the week Nadezhda receives a letter from Osip Abramovich, in which he demands that Petya return. Petya falls to the ground, cries, screams. Mother takes the boy to the city, and everything starts from the beginning. Only at night, Petka enthusiastically recounts his summer adventures to Nikolka.