The movie depicts the harsh realities of coal mining workers in a Moravian city (Ostrava).

The tale of the Venetian gondolier whose desire for revenge following a thwarted love affair leads him to Bohemia. The intricate plot also deals with destinies of other characters, who finally come together in a dramatic encounter at one time and in one place. In his role as screenwriter and director, Anton produced a highly accomplished version of Mácha’s work. He respected the original but was also able, along with the DoP Karel Kopřiva, to capitalise on the possibilities that the film medium offered. For the Venice prologue, the filmmakers exploited the photogenic qualities of the city – the narrow streets, the lagoons, gondolas and the sea – and they moved the set to the enigmatic Czech landscape around the castle of Kokořín.

Professor Grant signs a contract with Dr. Selin for the sale of his invention of cold light with the plans for his invention being kept in Grant's apartment. The negotiations are secretly heard by the illusionist Durk, who wants to seize the invention. A few days later Selín is found dead, killed by a light bulb filled with poisonous gas. Durk performs at the birthday party of Grant's daughter Anna and seizes the plans for the invention.