Aimed at the upper end of the YA age range, this is a story in two parts with two focus figures, Lena and Constance. Lena is a cryptling, one of the hidden people who service the revered Ancestors, condembed to that life because of a facial birthmark. When she is accused of being a mage and sentenced to death she bolts from the walled city of Duke's Forest and into the woods where she encounters Constance, who is a mage, and desperately trying to re-enter the city of her birth, a city to which she is heir. Constace is also a mage and her stated purpose is to destroy the spell which hangs over Duke's Forest ,a spell of cloud-darkness and corruption which will eventually cause the dead to rise. Constance directs Lena towards Emris, a hunter-mage, who takes her under his wing and initiates her into magical education. (She does seem to pick it up a bit too easily, but that's probably necessary to move the story forward and keep pace with Constance's narrative.) When it transpites that Lena has the key to the spell to which Constance is trying to find the key, and that Constance is in trouble, she heads back to Duke's Landing. There are some twists in this, two strong female leads presenting alternating storylines, and an interesting magic system. There's also an unreliable narrator element which is difficult for any author to pull off, but Ms Lupo manages it successfully.