Against John Cannon's advice, Mano helps Sean McLaren, an Irish miner, and his friends in their strike against dangerous working conditions.

McLaren and his friend Scanlon are sentenced to the chain gang for fighting with Cass Gregg, mine superintendent. Mano helps the two escape. John Cannon favors negotiations to improve conditions while McLaren insists sabotage will provide more direct results. When Scanlon is fatally beaten by Gregg, McLaren decides to destroy the mine, and Manolito appears helpless to stop him.