The Mráz family is preparing for holidays. Parents are traveling to the spa and little Petr is going to the country to his grandparents. In addition, to the chaotic preparations, mother's friend is bringing a dog Blek. She wants Petr to look after it. Grandfather welcomes Petr and the dog with pleasure because he needs the ally against strict grandmother. Grandfather is not very skillful and thus grandmother often experiences troubles with his ideas.

Surly solitary truck driver is given an assistant for his daily rounds: a young woman with a fondness for mini-skirts and boys, fresh out of prison.

Grammar school teacher Bláha hurts himself in pursuit of a red lizard, and is lying unconscious in the lonely house of Santrucek family. The postman, who found Bláha's coat and hat in the water, announces to everyone in town that the professor has drowned. But, the venerable citizens are at that moment more interested in the theatre group with the beautiful guest actress Eva Gazdová. They demand a change of repertoire and manage to persuade the theatre manager to have the group play the musical comedy The Red Lizard instead of an established play.

Vlasta Burian jako černý pasažér rozvrátí disciplinovaný chod jednoho nádraží. Pan Ťopka působí dojmem gentlemana trochu chaplinovského typu. Živí se příležitostnou prací, za níž jezdí výhradně jako černý pasažér vlakem. Při jedné jízdě se setká s obávaným generálním inspektorem drah Kokrhelem. Na jedné malé stanici se mu podaří vystoupit a převléknout se do uniformy přednosty stanice. Setkání s inspektorem Kokrhelem se však nevyhne... (oficiální text distributora)