Mull, Brandon, 1974- Dragonwatch (Series) #3

As the evil Celebrant conquers more and more dragon sanctuaries, Kendra must raise an army of friends and allies on her own to fight him because her brother Seth and Bracken are missing

Grades 7-9

Cursed by the Key of Forgetting, Seth has lost all memory of his past, and aligns with his new mentor, Ronodin. The dark unicorn takes him to the Phantom Isle, the secret gateway to the Under Realm. Though Seth is not formally a prisoner, Ronodin wants to use him and his shadow charmer powers for his own dark ends. Kendra's search for her brother will take her and Warren, Tanu, and Vanessa to Crescent Lagoon, a recently fallen dragon sanctuary. If they can save that sanctuary, they might uncover the answers they need to rescue Seth. -- adapted from jacket

670L