Country man Josef Bezoušek has gone to Prague for an extended visit to his lawyer son's family. His son, daughter-in-law and granddaughters have welcomed him with open arms, so the grandfather quickly gets used to them and really likes the metropolis. He enjoys walks and city attractions, and in the process he inadvertently gets involved in the story of his son's sister-in-law's forbidden love. She has lost her mind for a poor young man, her father does not want her to know him and imprisons the girl at home. The scoundrel Bezoušek inadvertently finds himself right in the center of the affair - and trouble is already coming his way. He himself could have endured it, but before leaving Prague he wants to settle the whole matter to the benefit of the unfortunate lovers...