The Girl Philippa (1917)

About the year 1900 in a midnight raid on the palace of a Balkan king, emissaries of a great power slay the royal pair, and carry off the infant crown princess. The time shifts to the present. Foreign agents steal the plans of a new shell loaned Great Britain by America. Halkett and Gray, English officers, recover the plans; and the foreign agents endeavor to gain possession of them again.