A New York Times Bestseller 

"Imaginative and entertaining … Readers will breathlessly turn the pages as they wonder: Can the duo solve the mysteries of The Nine in time to save it from those who wish it—and them—ill?" —Bookpage

"The department store offers a rich setting for adventure …. Mystery in a wondrous environment melds with family history and a tinge of magic in this tale for detail-oriented young readers." —Shelf Awareness

In this thrilling mystery from an award-winning author, Zander is determined to do whatever it takes to save his grandmother’s nineteen-story out-of-this-world department store—perfect for fans of The Swifts and The Mysterious Benedict Society.
 
Zander Olinga’s grandmother is the owner of the fabled Number Nine Plaza, the spectacular nineteen-story skyscraper. The Nine, as it’s called, has everything imaginable, including a massive Ferris wheel on its rooftop, monorail tracks suspended from its ceiling, and twenty-five glass elevators. But there’s something evil looming in the shadows, and strange accidents start befalling the guests. When Zander and his friend Natasha come across a series of inscriptions hidden throughout the walls of The Nine, they discover that the clues will lead them to a magical object which protects the store’s very existence. With the future of The Nine on the line, the pair are determined to recover the mysterious object before the luxury plaza and its many guests are destroyed. 
 
Featuring an unforgettable setting and a larger-than-life cast of characters, here is a spellbinding mystery involving puzzles, art, and high-stakes adventure.