In a small Scots mining-town, a mine cave-in seals the entire crew. The main shaft is flooded, and those who survive the collapse are encamped on a small patch of ground above the water. The mine telephone keeps them in communication with the surface, and Donald Sloan, the crew foreman, organizes the men below, and waits for instructions from above. The rescue squad, with the help of Margaret Wishart, one of the trapped-miner's wife, decide to follow an abandoned-shaft tunnel. When they do reach and cut through to the trapped men, dangerous gases seep in and the men are ordered to move further back. One of the rescuers, John Cameron, comes down to calm the men and to bring breathing equipment but there is only enough equipment for three men at a time to be brought up.