The Wolf's Heart: The Sorcerer's Saga, Book 6 (Unabridged‪)‬

There have been mixed feelings about the changes in Caldaca since the black star. Ayden and Merlin just want things to settle down for them at the castle. When Nimue shows up and tells them that Gmork has gone missing, it is only the beginning of their most exciting and dangerous adventure yet.   

This time, it will be their hearts that are tested. With the help of old and new allies, they must attain the heart of Baltezore, a dangerous weapon against dragons. To save the people they love, they will have to face old enemies, terrible curses, gruesome monsters, dark secrets, and their own flaws.