A Scheme of Sorcery

Palace squire Edwynne Dovecote has discovered her life is a lie. She wasn't born into the nobility- she's a daughter of the North, an inhospitable country where people worship a mysterious goddess. Even if it puts her at odds with her adopted family, she's determined to explore her heritage, as long as no one finds out who she truly is. But Sariva al-Beroth, an ambitious Northern girl who's started working for the queen, is sick of rude outsiders gawking at her culture.
She refuses to be in the same room as Edwynne, let alone share ancestral secrets. Then the queen falls under a curse, and only Sariva and Edwynne can rescue her. To save their country, they'll have to survive a ruined underground castle infested with ghosts, a fascist uprising prepared to sway public opinion with mind-control magic. and each other.