Maxime, a Val-d’Or native in his early twenties, works in an underground mine near his hometown. He’s on a 14 days on 14 days off schedule. He shares his life between his girlfriend with whom he’s patiently trying to father a child and his childhood friend Julien, now disabled following a car accident caused by Maxime a year before. Since then, guilt eats him slowly as he intends to redeem himself, only to find Mario, Julien’s father, on his path, slowing the process down. The father, who works at the mine with him, still holds a grudge for his role in the accident. One night, there is an explosion underground. Maxime heads underground that night with the firm intention to bring all his colleagues back alive. Through the daily life of these mine workers, Souterrain puts forward the contrast between the harshness of the setting of underground mines and the great humanity who work there.