Members of an organised group smuggling heroin from France to Italy send a new shipment of the drug via Sweden, the GDR and Czechoslovakia. A new ballet is about to premiere at the Fibich Theatre in Prague. However, the situation is complicated by a horrific event: prima ballerina Milada Havlová is found dead in her dressing room. The autopsy and the first analyses reveal that she died of a heroin overdose. Captain Chrástek is in charge of the investigation and believes that it is not an accident but murder. An investigation unfolds that reveals not only the strained relationships between the members of the ballet company, but above all an international criminal network...

The plot of the film follows a bus ride on the Prague - Karlovy Vary route and the actions of the people on it. A diverse group of people with various interests, professions and personalities gathered on the bus. Their encounter in the close environment of the bus gave the opportunity to create a whole series of good humorous situations. The ride on the express bus is a symbolic example of the contemporary life of our society, in which, just like when riding a bus, it is necessary to suppress many private interests and selfish qualities in order to successfully reach the destination.