After discovering the tomb of El Mokanna—the Veiled Prophet—and retrieving the precious relics buried there, the eminent archaeologist Sir Lionel Barton blows up the tomb. The heretic sect faithful to Mokanna interpret the fireball as their prophet's second coming, and a violent uprising begins.

Meanwhile, the insidious Dr. Fu Manchu senses an opportunity to use the powerful relics for his own evil ends. The action stretches from Persia to Cairo, then back to London, including an extraordinary confrontation inside of the Great Pyramid. Along the way his opponents face Ogboni killers, mind-control drugs, dervishes, and a "ghost mosque."