Even as he grows stronger and closer to discovering the secret of his identity, Arthur must face further dangers and conflicts as he struggles to attain the Sixth Key from the powerful Saturday. Best-selling author Garth Nix creates a magical world and an intriguing mystery in this new blockbuster series. Seven days. Seven keys. Seven virtues. Seven sins. One mysterious house is the doorway to a very mysterious world—where one boy is about to venture and unlock a number of fantastical secrets.