From the author of the bestselling The Dangerous Book for Boys The Great Khan is dead--and his vast empire, forged through raw courage, tactical brilliance, and indomitable force, hangs in the balance. Now, with the sons of Genghis Khan maneuvering for supremacy, the very qualities that united the fierce Mongol tribes threaten to tear them apart. Genghis's tough and canny heir, Ogedai, is on the verge of becoming the new Khan. Inexplicably, Ogedai has delayed his coronation to complete a project many deem a folly: the building of Karakorum, a magnificent city amid the wild plains. His decision emboldens his arrogant brother Chagatai to violently challenge him, leaving their noble sibling Tolui caught between them. Yet even as they clash, the Khan's armies extend his reach farther than ever before, into southern China and across the rugged mountains of Russia to the vulnerable heart of Europe, where the most courageous warriors the West commands await the coming onslaught.