Diana Harrington was sweet and virtuous, but her twin sister, Demanda, was swept up in scandal -- she had married the Earl of Weston's younger brother only to have him die in a duel over her honor. After an accident that left her unconscious, Diana awoke on the Earl of Weston's estate and discovered that everyone thought she was Demanda. When she overhears a plot to murder the earl, she must continue the charade to save his life.