The film takes place in August 1934 in the Polish part of Upper Silesia. The film tells the story of a strike in the fictional mine "Zygmunt". Jaś, a young miner who works in the mine, has a wife and two young sons. Jaś comes home from his shift. The next day he learns that the unprofitable mine is to be closed by flooding with water. A strike breaks out. Families help the strikers, despite the fact that the mine is surrounded by a police cordon. Petitions to the Government go unanswered, the management persists, so the miners announce a hunger strike. The police retaliate by violently breaking up the demonstration. The determined miners decide to continue the strike underground despite the imminent threat of the mine being flooded. Finally though, the management signs a settlement, and the miners come to the surface and go back to their families.