The strike breaks out and is particularly well attended at all the pits. It even gained momentum in the face of inflexible management. It was the beginning of another hellish period on the horizon, that of hunger. The meagre savings of the revolting group would not last long. All the more so as the company has sent in its heavyweights, commanded by Bressan, to break up the movement. Faced with these threats, some decided to give up and head for the Jean Bart shaft, where the miners had not stopped work. Chaval, for example, forces Catherine - whom he now has under his thumb - to come with him. Faced with the risk of demobilization, Etienne manages to keep the miners together.

The march quickly took on the air of a revolution. At the Jean Bart shaft, strikers destroyed the installations, forcing the miners to the surface. The crowd of miners then headed for the other shafts. Everywhere they went, they engaged in acts of vandalism, despite their fear of the gendarmes. Tempers flared. The antagonism between Etienne and Chaval, who wants to break the strike, reaches a climax. They come to blows with knives. Catherine steps in and defends Chaval. Still in love, Etienne experiences this as a heartbreak.

Despite all this suffering, the workers still refuse to give up the strike. Perceived as the strike leader by the authorities, Etienne had to go into hiding to escape the gendarmes. He only goes out at night to join his comrades. The situation takes a dramatic turn for the worse when Belgian workers arrive from overseas to restart production at Le Voreux.

Etienne realized his failure and fell into despair. Some, like Maheude, don't want to give up, but they're in the minority. Most agreed to go back to work. But they don't know that Souvarine, true to his principles, has sabotaged the Voreux shaft. As the miners descend in the morning, an accident occurs.