The documentary First of May explores the more than a century-long evolution of the celebration and the meaning of this day. The structure is composed of memories, newspaper excerpts, testimonies found in archives, etc. - all these passages are brought to life by the actors' voices, taking on the roles of journalists, factory workers, policemen, workers and ordinary people who watch May Day, sometimes with interest and verve, sometimes with distance or irony.

"A documentary anatomy of mass murder for one monitor and 34 talking heads." These are the words the filmmakers use in the credits to describe their project, which thematises the execution of more than 260 Carpathian Germans, Hungarians and Slovaks by Czechoslovak army soldiers near Přerov in June 1945. The “massacre at Přerov” is made present through a minimalist dramatisation of the interrogation footage of direct participants, eyewitnesses, and others. It is as if the characters of ancient theatre were entering the Zoom “stage” and delivering a tragic message of fear, hatred and disinterest across the chasm of time.