Prince Ben and Princess Cecily are dragonborn. Since birth, the brother and sister have shared a body, shapeshifting from one form to the other each sunset. In exchange for this magic, they have been promised from birth to a mysterious dragon, who is set to collect on their twentieth birthday, which is now just weeks away. With the help of two tutors, a bodyguard, and a foreign princess, they must find a way out of the betrothal, delving into their kingdom's history and learning to harness their magic—all the while challenging the kingdom's laws and restrictions on love.