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.

Thirty-five-year-old bachelor Jiří Šafránek is a train dispatcher, an amateur actor rehearsing the role of Hamlet, and the proud owner of a 1960 Stadion 22 moped. Because of the blue color of his beloved motorcycle, the police call Jiří the Blue Dragon. Jiří still lives with his mother, who finds it difficult to tolerate his escapades. Like Prince Hamlet, Jiří talks to his father's ghost. In addition, he is always running late and shortens his journey from work to theater rehearsals by taking a footbridge where motorcycles are prohibited. One day, he almost collides with a girl named Adina coming in the opposite direction. This marks the beginning of a relationship that will disrupt not only Jiří's coexistence with his mother, but also the preparations for the premiere of Hamlet itself.