The centerpiece of this tale from Don Carlos Buenaventura's third life as a brujo is his encounter with Don Malvolio, a malign sorcerer whom Carlos had previously known only as the ancient enemy of the small brotherhood of benign sorcerers, the Sun Moiety, to which Carlos belongs. In MONTEZUMA'S EMERALD Don Carlos meets Don Malvolio in the flesh for the first time, and the enmity between the two of them ceases to be abstract and becomes personal. The stakes are high. If Malvolio obtains possession of this emerald, which once belonged to Montezuma II, the last emperor of the Aztecs, it would give him the power to rule the world.