The second spy / by Jacqueline West ; illustrated by Poly Bernatene.

Enhanced descriptions from Syndetics:

In Olive's third adventure in the New York Times bestselling Books of Elsewhere series, what lurks below the house could be as dangerous as what's hidden inside. . .

Some terrifying things have happened to Olive in the old stone house, but none as scary as starting junior high. Or so she thinks. When she plummets through a hole in her backyard, though, Olive realizes two things that may change her mind: First, the wicked Annabelle McMartin is back. Second, there's a secret below-ground that unlocks not one but two of Elsewhere's biggest, most powerful, most dangerous forces yet. But with the house's magical cats acting suspicious, her best friend threatening to move away, and her ally Morton starting to rebel, Olive isn't sure where to turn. Will she figure the mystery out in time? Or will she be lured into Elsewhere . . . and trapped there for good?

A must-read fantasy series for fans of Pseudonymous Bosch, Coraline , and Septimus Heap.