A comedy about exchange of 12 apartments , which, its organizer, lawyer Radosta, rightly called Action Ball Lightning. To prepare, organize and execute the exchange of twelve apartments is a work worthy champions. Radosta, who was excellently played by Rudolf Hrušínský, solved all sudden difficulties and complications on the fly and with grace. To be sure that the on the D-day everything goes well he prepares a little rehearsal, which reveals many minor issues caused for example by wedding ordered to inappropriate term or hesitation of some participants. Last but not least a night exercise announced by drunk psychologist Knotků, creates a lot of confusion that nearly sabotaged the whole operation.
The town is waking up. The bus driver Josef Král is saying goodbye to his wife Vera who is in a state of advanced pregnancy. At the rolling mill, the master craftsman Mares is preparing for retirement, which is now only two days away. Elderly Simon who grows and sells vegetables at the market has problems with his wife. Their little home has to give way to a new development but the wife Simonka refuses to move out. The chairman of the workers' council has troubles with the miner Adam, who has started drinking. He doesn't know that Adam is getting divorced and fears he may lose his young son to his wife.
This comedy is about one average family. The father works as master in the factory and his son is studying on high school. One day father must start to visit the evening school. It's the same school as his son visiting. The lives both students are connecting together. The son must teach the math and physics his own father. The father getting to know, that the life of the students is not simple as he supposed.