The Tears of Elios — Crista McHugh

Shape-shifters' Rule #1: Don't let the humans know you still exist. Rule #2: If a human finds out about you, silence them. Some rules were meant to be broken… Ranealya ruthlessly plays by the rules and has outlived most of her race because of it. If she wants to survive, she'll have to stick to them, especially with a genocidal tyrant hell-bent on destroying all the non-humans in the realm. But everything falls apart when a human saves her life. Gregor knows he's inviting trouble when he helps a wounded shape-shifter, but he can't pass up the opportunity to study one before they become extinct. She disturbs the quiet order of his scholarly existence, vexes him in more ways than he can count, and encourages him to break enough of the kingdom's laws so that not even being the king's cousin will save his head. The problem is, he's already lost his heart.