French General Birabeau has been sent to Morocco to root out and destroy the Riffs, a band of Arab rebels, who threaten the safety of the French outpost in the Moroccan desert. Their dashing, daredevil leader is the mysterious "Red Shadow", a Frenchman. The Red Shadow, his Arab lieutenant, Sid El Kar, and their wealthy host, Ali Ben Ali, discuss the relative merits of the Eastern tradition of love for a harem of women (like having a garden full of fragrant flowers), and the Western ideal of loving one woman for life. Margot Bonvalet, a lovely, sassy French girl, is soon to be married at the French fort to Birabeau's right-hand man, Captain Fontaine. Birabeau's son Pierre, in reality the Red Shadow, loves Margot, but pretends to be a milksop to preserve his secret identity. Meanwhile, Benny, a reporter, and Susan, the girl who loves him, provide comic relief.
Margot tells Pierre that she secretly yearns to be swept into the arms of some bold, dashing sheik, perhaps even the Red Shadow himself. Pierre, as the Red Shadow, kidnaps Margot and declares his love for her. To her surprise, Margot's mysterious abductor treats her with every Western consideration. Benny and Susan are captured too. When the Red Shadow comes face to face with General Birabeau, the old man challenges the rebel leader to a duel. Of course Pierre will not kill his own father, so he refuses to fight, losing the respect of the Riffs. Azuri, the sinuous and secretive native dancing girl, who knows the secret of the Red Shadow's true identity, might be persuaded to reveal the information if she could capture the attention of Captain Fontaine. Eventually, the Red Shadow's identity is discovered, a deal is struck with the Riffs, and Pierre and Margot live happily ever after.