Synopsis by Hal Erickson
The Soldier's Oath begins in France at the outbreak of WWI. Drafted into the French army, William Farnum must first keep a promise to a friend and deliver a valuable collection of jewels to the friend's wife. After he fulfills this obligation, he is accused of murdering the woman and stealing the gems. Sentenced to life imprisonment, Farnum is pardoned after ten years thanks to his bravery during a prison fire (meaning that the rest of film takes place in the "future" year of 1924). Upon returning home, he discovers to his horror that his now-grown daughter is about to marry the man whom Farnum suspects to be the actual murderer. The culprit outsmarts himself when he gives the girl her engagement present -- the very jewels which he had stolen a decade earlier. Evidently, the Fox editing department shipped out a "rough cut" of A Soldier's Oath for its New York premiere; the print was splicey and scratchy, with several subtitles out of order.