One explosion takes place in the lab of the research institute of a chemical plant. Emil takes the blame. The director of the institute orders the work on the case to be suspended. After his jail sentence, Emil equips a lab in the dwelling he is renting. A little before the end of experiments there is another explosion. Emil is in the hospital. A friend announces him that the experiment was a success. Next to Emil is the girl he loves.

A story about three brothers, Petar, Angel and Vasil, each one joins the fight against fascism in his own way.