Geoffrey Radcliffe, the wealthy owner of a coal mining operation, is running out of time. In two hours, he is set to be executed for the murder of his brother, a murder he did not commit. His fiancée, Helen Manson, is frantic. Geoffrey's cousin, Richard Cobb, tells her that he has done everything he can. Geoffrey's only hope is his friend, Dr. Frank Griffin. Griffin's late brother once discovered a secret drug that makes a human being invisible. The only trouble is, it also turns its subject mad. But now Geoffrey, Helen and Dr. Griffin have no other choice.