Three brothers are being brought up by their ostensibly wealthy aunt at her country home. Her estranged husband, however is bleeding them dry. Many years pass and the boys grow to respectable manhood. Then a cable arrives asking her to arrange to value their last asset - the famous "Blue Water" sapphire. She has it fetched from the safe, but suddenly the lights go out - and the jewel is gone. Only the young men and the butler are in the room - who could have taken it? Next morning, all three have admitted the theft and have absconded to join the French Foreign Legion! They are posted to a remote fort under the command of the brutal "Lejaune" (Noah Beery) who hears tell of their stolen jewel and conspires to pinch it from whichever of the "Geste" boys has it... It's a cleverly contructed story, this. Even though we, the audience, have a pretty good idea what really happened, there is still a hint of jeopardy as their travails in the desert against their ruthless sergeant, the heat - and the marauding tribesmen - gathers quite a rapid pace. In theory Ronald Colman ("Beau") takes top billing, but together with his on-screen siblings Neil Hamilton ("Digby") and Ralph Forbes ("John") they all, pretty much equally, keep this exciting adventure story moving along a-pace , with plenty of action and grand cinematography (ok, Arizona - not Morocco). There were plenty of talkie version of this film made subsequently, but none quite as good...