Mahali's rulers for generations were the water witches, who could feel the ebb and flow of precious water in their very bones. Then there was a coup, and control of Mahali's water passed to an impersonal computer network.
It was Deza's father who hit upon the scheme. Dressing his daughter in ceremonial garb, he passed her off as the last surviving member of the royal house. With tricks and illusions she and her father moved toward the centres of power.
But it's the nature of a con artist to go too far . . .