Desc: The Mystery Girl: Directed by William C. de Mille. With Ethel Clayton, Henry Woodward, Clarence Burton, Charles West. Prince Sebastian of Lurania is forced to go into hiding when German forces invade his country. His niece, Countess Therese, is an ambulance driver with the French army, and one day she hears from her uncle, who requests that she meet him in a small town in Maine and bring the crown jewels with her. Unfortunately, a jewel thief finds out about the meeting and makes a deal with the Luranian pretender to the throne: he will steal the jewels and he can keep them if he kidnaps and turns over the Countess to the usurper.