Thirteen-year-old Dan Cahill and his older sister, Amy, are the latest guardians of the Clues -- thirty-nine ingredients in a serum that transforms whomever takes it into the most powerful person on earth. By Rick Riordan and other authors. Teen fiction. Preloved condition with no major flaws. All books are hardcover and are looking for a loving new home! Exclusive Collector’s Edition Poster 5 bonus codes 72 cards TITLES IN THIS SET Book 1: The Maze of Bones Book 2: One False Note Book 3: The Sword Thief Book 4: Beyond the Grave Book 5: The Black Circle Book 6: In Too Deep Book 7: The Viper's Nest Book 8: The Emperor's Code Book 9: Storm Warning Book 10: Into the Gauntlet Book 11: Vesper's Rising + The 39 Clues: The Black Book of Buried Secrets + Cahills vs Vespers: The Medusa Plot (Book 1) Each book retails for $13 for a retail price of $169, selling for half that!