Brothers Beau, John and Digby Geste join the Foreign Legion, where they fall under the rule of tyrannical Sergeant Markoff. Beau and John are assigned to Fort Zinderneuf, where Markoff tries to break their spirit, aware of a dark family secret concerning a fabulous jewel one of them carries. As tensions rise, Arabs attack the fort and rivalries must be thrown aside in a desperate battle for life.

When Marcel, a waif, saves master crook Burke from the police, Burke adopts the youngster and teaches him his profession. Years later, Marcel has become a master crook himself, working under the name of Michael Lanyard. His clever work baffles the Paris police, who dub him "The Lone Wolf". The Pack, a gang of criminals, notifies The Wolf that unless he joins them, he is marked for destruction. Lucy, an undercover agent masquerading as a crook to expose the gang, helps The Wolf escape. This inaugurates a series of adventures in which Lucy and The Wolf are pursued by the gang, finally making their escape to England by plane. The Pack follows, only to meet their death in a plane crash. Liberated from his tormentors, The Wolf vows to go straight and marries Lucy.

Wilfred of Ivanhoe (played by King Baggot), son of Sir Cedric (played by Wallace Bosco), returns to England from the Crusades in the Holy Land. As Ivanhoe, disguised, discovers that his beloved Lady Rowena (played by Evelyn Hope) has remained faithful, two weary travelers, Isaac of York (played by Herbert Brenon) and his pretty daughter Rebecca (played by Leah Baird), are admitted to Sir Cedric's castle, but after the knights learn that Isaac has money they abduct the visitors to the Norman stronghold of Torquilstone Castle.