The Sandsea Trilogy

Loulie al-Nazari is the Midnight Merchant: a criminal who, with the help of her jinn bodyguard, hunts and sells illegal magic. When she saves the life of a cowardly prince, she draws the attention of his powerful father, the sultan, who blackmails her into finding an ancient lamp that has the power to revive the barren land—at the cost of sacrificing all jinn.