The parents of twins Petr and Pavel are leaving for Afghanistan to build a dam. They entrust their offspring to their uncle Podlipný in Gottwaldov. The boys soon make friends with their new classmates. They are a little envious of their uncle, the pilot, because almost the entire class is interested in airplanes and attends a model-making club. Here, under the guidance of instructor Dáša, they build a model of an OK 12 airplane, with which they want to participate in a competition. The children assume that both Prague boys are also good at model-making. Petr and Pavel are ashamed to admit that they know nothing about this activity. To save their reputation, they decide to secretly learn it themselves.

High school students experience the everyday worries of their age - they prepare for their high school graduation, go on a production internship at an engineering plant, and compete for a ski trip to the Krkonoše Mountains...