Court of Venom

The city of Aran lies at the center of The Lost, a desert haunted with ghosts, demons, and witches, who prey on those with regrets and fears. Twelve year old Badriya and her mother, Sireen, risk the journey from their home on the coast, fleeing tragedy.
The King of Aran falls in love with Sireen, despite his Queen and daughters, Solena and Najma. The Queen and her court ostracize Sireen. After striking a bargain with the Queen, Sireen throws herself from the wall. Badriya discovers that her mother is held hostage by a desert Witch, who promises to set Sireen's spirit free, in exchange for one hundred silvers. So Badriya sells potions and cosmetics to the city's courtiers, including Solena, to raise the ransom.
The King, driven insane with grief and alcohol, becomes obsessed with Badriya and kisses her. He dies immediately. Solena, now the Queen, orders Badriya to become her assassin in order to make amends.
Several years pass. Prince Arlo comes to request Solena's hand in marriage. Badriya, now eighteen, discovers that Khalen, Arlo's adviser, can see ghosts of his own. The two strike up a tenuous friendship, until Solena orders Badriya to assassinate the Prince. A grateful courtier has paid Badriya enough silvers to free her mother. So she decides to warn Arlo away, but Solena murders him anyway. As Badriya prepares to flee, Khalen intercepts her and orders her to assassinate Solena. If she does, he will help her free her mother; if she refuses, he will leave Badriya to die.
Badriya returns to the city to confront Solena, but Najma poisons Solena, then orders Badriya to leave Aran and never return.
Badriya flees and finds the Witch. She trades the silver for her mother's freedom. Khalen offers his horse so she might outride the ghosts and demons of the desert and return to the coast, and freedom.