Summoned by an Indian princess, Tarzan travels to India where hundreds of wild elephants are in danger. A company is building a hydroelectric dam and the contractors have only a few weeks to finish the job. The building of the dam will flood the valley surrounded by mountains. There is one pass through which the elephant herd can escape but that is being closed. Tarzan comes up against an old nemesis, Bryce, the chief engineer. Bryce undertook a similar dam project in Africa and had a penchant for shooting elephants. It's up to Tarzan to organize the move before Bryce manages to close the pass.
Después de la Guerra Civil (1861-1865), el capitán Porter es destinado a Texas. Su esposa no quiere acompañarlo, pero él la convence para que vaya y proteja a los más necesitados de las especulaciones de los ricos. Uno de ellos, Balfour, compra una partida de grano en pública subasta, pero Porter le niega la protección que solicita para trasladarlo. Aprovechando la ocasión, unos bandidos atacan e incendian el vagón del tren que contiene el grano. Tras ser amonestado por sus superiores, el capitán se propone encontrar a los culpables.
Shiek Yousseff, poses as a friend of the French while secretly plotting to overthrow them. Apposing Yousseff are the Riffs, whose secret leader, The Red Shadow, is Paul Bonnard, a professor who is studying the desert, and whose attacks on the supply trains intended for Yousseff keep the Riff villages in food. Foreign Legion General Birabeau arrives to conduct an investigation, accompanied by his daughter, Margot. Birabeau hires Bonnard to tutor her, and she is attracted to a Legionaire captain, Claud Fontaine. While the general, Bonnard and Fontaine pay a visit to Yousseff, an American newspaper man, Benji Kidd, discovers a secret way in and out of Yousseff's palace, with the aid of Azuri, a dancing girl in love with Bonnard. The latter is forced to resume his role as the Riffs leader, and kidnap Margot until he can convince her of Yousseff's treachery. But Yousseff's men attack the Riff camp and take Margot prisoner.
