Mercy Merrick, a beautiful young English woman, is the victim of a heartless man. When she learns that he is married she is about to commit suicide and is prevented from doing so by Julian Gray, a young curate. Determined to redeem herself, Mercy enlists as a Red Cross nurse in the Franco-Prussian war. Grace Roseberry is on her way to England to be adopted by her relative Lady Janet Roy, and in passing through the lines she is struck by a piece of shell and left for dead. Mercy Merrick exchanges clothes with Miss Roseberry and takes her letter of introduction, goes to England and is adopted as Grace Roseberry and saves her life. Julian Gray, who is Lady Roy's nephew falls in love with Mercy Merrick, not recognizing her as the woman he had saved from suicide. They are engaged to be married. The real Grace Roseberry is about to be taken away as a lunatic when Mercy Merrick's best nature asserts itself and she declares herself to be an impostor and saves the other woman. In a touching scene, Mercy Merrick goes to bid farewell to Julian Gray and to give him his ring, but the noble young minister tells her that she has suffered enough, and as his wife, the repentant Mercy finds a true shelter.