Sun and Moon, Star and Snow (Zuko X OC)

A waterbender, raised in the Fire Nation and trained to be a deadly assassin, follows her heart after her prince gets banished. She travels with him all over the world, from the Air Nomad Temples, to the Southern Water Tribe. There, they find the Avatar and capture him.
But on their way out, the assassin is forced to make a choice that could change the war: her prince, at the cost of the world, or the world, at the cost of her prince?

I DO NOT OWN ATLA OR THE COVER OF THIS BOOK. I ONLY OWN THE MC.