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.

Autumn 1968, the Australian running record holder Ron Clarke is coming to Prague, hoping that his old friend and role model, Emil Zátopek, the most famous Czech athlete of all time, will help him overcome the biggest crisis of his career.

The Inspector Hynek Budik as been assigned chief of police in the area on the outskirts of Prague, With detectives Martin Novacek an inexperienced rookie and the inspector Havlik will seek to solve difficult cases of murder.