Best-selling author Rick Riordan presents the thrilling conclusion to Roseanne A. Brown's middle grade trilogy about a pre-teen girl who, as half-Slayer and half-vampire, is caught between two worlds. Serwa Boateng has gone head-to-head with vampires, witches, and even a death god. But now, with the fate of the magical world at stake, she'll have to face her toughest foe yet: her own grandmother. Finally free after decades of...