D'Artagnan and his fellow musketeers vow to defend France's Princess Anne to the death. It seems that Anne has been thrown into a dungeon with her face enveloped in an iron mask, while her long-lost sister Louise is placed on the throne by scheming Duke De Valdac. D'Artagnan and his pals must rescue the princess before the impostor goes through with an arranged marriage to
King Phillip of Spain. Louis Hayward, Patricia Medina, Alan Hale Jr.