The fourth book in the New York Time s bestselling series by Jessica Day George, where a dangerous wizard threatens to destroy Castle Glower for good . Fridays at Castle Glower are about to get interesting! With newborn griffins hatching left and right, new Castle passageways to explore, and an out-of-the-blue wedding to plan, life is as exciting as ever for Celie, Lilah, and Rolf. But when the dangerous, ancient wizard Arkwright escapes from the dungeon, no one can rest until he is found. Celie has an idea of where he may be hiding, but the only way to stop him could be to erase parts of the Castle for good. With danger lurking behind every tapestry and under every trapdoor, can Celie outsmart Arkwright fast enough to save her family and Castle Glower? Don't miss these other stories from New York Times bestselling author Jessica Day George: The Rose Legacy series The Rose Legacy Tuesdays at the Castle series Tuesdays at the Castle Wednesdays in the Tower Thursdays with the Crown Fridays with the Wizards Saturdays at Sea Dragon Slippers series Dragon Slippers Dragon Flight Dragon Spear The Twelve Dancing Princesses series Princess of the Midnight Ball Princess of Glass Princess of the Silver Woods Sun and Moon, Ice and Snow Silver in the Blood.