Elissa’s Quest by Erica Verrillo hit most of the major Girls Underground tropes and was an enjoyable enough read, but failed to really stand out for me; it is the first book of a trilogy, but I doubt I’ll be reading the rest of them.
Elissa believes she is an orphan, having been raised by an old healer, with no knowledge of her real family. She keeps a potent secret: she can talk with animals, and they are her only companions in an otherwise lonely life. One day, her father shows up and takes her away, hoping to use her in his plan to win a war. It turns out she is next in line to be royalty, a shock for the peasant girl. Elissa takes along her best friend, a donkey, who rescues her when she is captured by the enemy. Back with her father, Elissa chooses her own fate this time, electing to go to the palace of the Khan instead of back to her old life. There she makes a new friend and companion, a young slave girl named Maya.
Maya takes Elissa underground to a secret lake for a coming-of-age ritual that ends with the discovery of a small, insignificant-looking item that will prove important. Then she takes her to a wise woman, who speaks cryptically of things that hint at Elissa’s true power. The Khan is planning to wed Elissa and kill Maya, but they are rescued (and captured, and then escape into the desert and are rescued again – there is a lot of this type of action), and then Elissa is enlisted by a group of ancient healers to defeat the Khan. She uses her latent magic to destroy him, one on one.