A Flash in the Dark.

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.