Candlewicke 13: Under the Crescent Moon: Book Three of the Candlewicke 13 Series

Guided by a prophecy conjured by their secret coven of Sorcerers, Valor McRaven and his sister, Doomsy Gloomsy, return to Mystic City where they are being hunted. While trying to become apprentices of magic at Mystic Steeples, they battle ghosts connected to their past in a haunted mansion, investigate mysterious murders and disappearances, meet many suspicious witches who try to control them, and travel back in time through a book that seems to be steering them closer to the truth of The Great Deception.