The drama of a workers' family taking place in Upper Silesia at the time of a referendum.
Barbara, a Polish miner’s daughter, has fallen in love with Kurt a German citizen. Polish miners begin a strike to express their dissatisfaction with the results of the plebiscite. A military uprising is underway. When the agreement is signed the miners return to work. Germans recruit Kurt for a sabotage mission. His task is to blow up the dam and, in consequence, to flood the mine. Elderly Milcarek finds him setting up the explosives. Kurt hurts him badly but he dies killed by Karol, Barbara's brother. Elderly Milcarek saves the mine by extinguishing the fuse with the last of his strength.
