The story of how students of grade 9 underwent summer practice at the motor depot, which patronizes their school. Krosh had no technical inclinations; he wanted to get a car during practice to drive. But together with Shmakov Peter got into the garage. At first they didn’t trust anything, they just watched. In the garage, the workers considered Krosh to be small, but after he showed them his rights, albeit for children, this impressed everyone. Gradually, the guys got involved in the work.

Igor worked in an office, went to workshops and filled out forms. He acted as if he were the deputy chief engineer. He loved to hang around among the elders, to be in the spotlight.

At the class meeting, after a week of practice, Igor suggests restoring the decommissioned GAZ-51. All the guys support him. Krosh offers, before embarking on such a difficult matter, look at the condition of the car. Nobody listens to him. As always, Igor offers something, and if it doesn’t work, everyone but him is to blame.

Krosh offers to make a defective statement. At this time, in the table near Lagutin, he finds bearings that he had to put on the car. The car left the garage with old details. The boy cannot believe that Lagutin can do this to the state - to sell bearings, and take the money for himself. Krosh realized for himself that Lagutin is a swindler.

Krosh, Shmakov, Vadim and Igor live in the same yard. Igor did not introduce the rest to his adult friends. He was shy. Vadim, as a friend, was hurt.

The next day, Vadim announced to all his classmates that they should collect everything that could fit their car. Just at that time, new shock absorbers disappear. Krosh guessed who took them - Lagutin. Immediately revealed the loss in other warehouses. All the missing things, except for shock absorbers, were in a warehouse reserved for students. Igor began to blame Vadim for this, although he himself was to blame - he told Vadim that the director allowed collecting things on the shops. From this moment, Vadim gets out of the influence of Igor. The guys apologized. The students were told to look for shock absorbers.

The guys were advised to restore the decommissioned car, which is located in Lipki, as it is in the best condition. Krosh, Shmakov, Igor and Vadim followed him. An accident occurred on the spot: the guys turned this car over. Krosh, Shmakov and Vadim were left to spend the night in a car, as they were ashamed to return to the city without anything. And Igor returned home, supposedly to warn relatives. When the children and the car were in Moscow, the parents made a fuss. The director reprimanded Zuev. Krosh wants to write a statement, because the guys are to blame. Igor discourages, and Zuev doesn’t care.

Igor tells Krosh that there are rumors that Zuev had taken shock absorbers. The boy decides to talk with Lagutin. A locksmith is distorting the words of a schoolboy, and already the entire motor depot knows that Krosh thinks that Zuev took the shock absorbers. Krosh is looked with reproach. The boy is suffering, because he wanted the best.

Vadim finds shock absorbers and shows Krosh. They decide not to pick them up and thereby go to the thief. In the evening at the dance, Mike dances with Lagutin. Krosh decides to never talk to her.

The next morning, the shock absorbers were not in place. The boys studied the tracks: some from the Volga, others from the all-terrain vehicle. Krosh talks about everything to Shmakov.

Students were given an advance. Krosh thoughtlessly spent almost the whole day. At Shmakov they remained intact.

Krosh writes a statement that Zuyev was not guilty of Lipki. The director is angry and asks not to interfere in any business.

The car restoration case was moving slowly. Only Krosh and Shmakov did almost everything. But then all the children were forbidden to do repairs during working hours. At the meeting, they decided that they would do it after their shift, and the masters would help them. Things went faster.

On Sunday, Krosh and Shmakov decided to go swimming in Khimki. Vadim was imposed with them. In the courtyard I meet Igor, who is messing with his Muscovite brother and cannot fix it. Krosh and Shmakov help him. Igor, in fear of another car breakdown, takes the boys to Serebryany Bor, where it is much better. There he meets his friends and moves away from classmates. In the end, everyone gets to know and swim together. Krosh pays attention to the traces of the car on which Igor’s friends arrived. They are the same as at the crime scene.

Krosh talks to Mike again and tells her the story of the shock absorbers. The guys decide to talk to Igor for cleanliness. Igor invites his friends on the Volga and it turns out that they did not take shock absorbers. But this could be done by the person to whom they gave their car for repair. And it was Lagutin with a friend. After some time, the whole class knew the story with shock absorbers. Lagutin looked askance at Krosh. Krosh and Shmakov talking with Lagutin. In the evening, dispatcher Zina comes to Krosh. The boy convinces her that if there are shock absorbers, then there will be nothing to Lagutin.

On the last day of practice, the car is finally ready, there were ill-fated shock absorbers and the director of the car depot first scolds, and then praises Krosh for honesty.