Randall is a rich mine owner whose business affairs cause him to neglect his somewhat frivolous wife. There is a mutual friend whom Randall carelessly allows to entertain his wife. As a result, the friend pays more than natural attentions to the woman. The three visit one of Randall's mines. The wife and friend go down the mining shaft in a bucket. While they are yet underground, a quantity of dynamite explodes. The mine is filled with poisonous fumes. Randall has himself lowered into the smoking shaft. He finds his wife and friend almost overcome. There is room in the bucket for two persons only. Randall places the two in the bucket and they are hoisted to the surface. The bucket is again lowered and Randall is brought up. The long period in the poisoned atmosphere has rendered him stone blind. The young wife soon tires of her blind husband. One day Randall overhears their plans for elopement. He goes to the friend and the faithless wife and explains that he has overheard. He then gives the man a revolver and tells him, "Turn out the lights and our chances will be equal." The woman turns off the lights. Both men fire and miss. The friend sneaks to the switch and turns on the lights, intending to change the duel into a murder. But the woman by this time has discovered which of the two is the man. She wrenches the revolver from the friend's hand and tells him to go and never return.