A picture about an adult who turns out to be completely unadapted to an independent life. He cannot write a letter to his mother, whom he so dreams of finding, he is not able to pay off the seller in the store. At the age of 20, Pyotr Kasikhin does not know the alphabet, and elementary children's puzzles with birds sitting on a branch seem incomprehensible. No, he is not a fool, as many people think he is. I just ended up in a mental hospital once. And it seems to be by mistake. Petr was diagnosed as "unlearned" and was not sent to school. Against all odds, Peter, who has long matured, goes to first grade. And let others laugh!