It was in May.

Worker Šebesta does not rejoice with the others in the May Day parade, as his boots are weighing him down. The following working day does not bring him a good mood either. At a plant-wide meeting, he comes into conflict with the young striker Brejcha from the United Engineering Works. He demands an increase in the production of heating elements so that the new hall can be completed before the deadline. The workers react to his passionate speech about the improvement efforts with distrust and, with a bit of mockery, challenge him to prove his words with action in their plant...