Danny Canavan, the big son of a tough Irish-American blacksmith, is actually not as tough as he looks--he's constantly abused by his wife, his scornful father and his father's employees. One day he is run over by a carriage owned by Rodman Cadbury, the president of an insurance company. Unable to work as a blacksmith anymore--something his wife constantly throws in his face--he gets a job on the subway as a flagman warning traffic of upcoming dynamite blasts. As menial as the job seems at first, it actually begins to change Danny's life.