In Heredity, the final book in the series, Marta and Brennan return to Asherill only to find that Cressidea and her army have arrived there ahead of them. The queen is determined to reclaim the land of Asherill as a part of Casteron, but the discovery that her cousin Xavier has joined up with the siblings forces her to fall back on old plans to create an heir for herself. With new allies as well as old, Brennan and Marta try to avoid capture while plotting to defeat the queen and restore Asherill to Lord Dracon's control. Confronted with friends who prove false and a very special ally who they know nothing about, they make their way into Aardendale and their final meeting with Cressidea, hoping that they will succeed where all others have failed.