When Deputy US Marshal Frank Dalton is killed in the line of duty, his brothers Bob and Grat are appointed to replace him. However, when they discover corruption in the higher echelons of the Marshals Service, they resign in disgust. Grat is cheated by a crooked gambler and takes back his money at gunpoint, but that winds up getting them labeled as robbers. Grat is wrongly accused of train robbery and imprisoned. When he breaks out of prison he and his brother decide to take their revenge by actually robbing the express company that falsely accused him in the first place.

The story takes place in a small struggling mining town located in the foothills of the California mountains at the time of the gold rush. The camp is suffering from a long string of bad luck. With only one woman in their midst, it seems as though the miners have no future. However, the tide turns when a small boy is born. "Thomas Luck" is the first newborn the camp has seen in ages; things are looking up.