An elderly rich lady, Hyacinta Horáková, is leaving for a spa. She entrusts her terrier Bobík to her sister-in-law Ludmila and her daughter Marcela, who live in her villa. The dog mysteriously disappears before long and there is no choice but to publish an advertisement promising a reward. In the newspaper's administration, advertising artist Ludvík Zoubek notices Marcela. He would like to please the girl who has charmed him and starts looking for the dog...
