“Hello!” it said, and hopped to the floor. The army of spiders ran for the window and disappeared through the cracks between the panes, giggling the whole way.

Miss Millie had stopped screaming and was now sobbing, because she knew where the spiders had come from. “She said it would play tricks, but she didn’t say anything about spiders!”

“What? Who?” said Dr. Munsterberg. “Miss Theresa?”

“No,” wailed Miss Millie. “The other girl.”

“What other girl?” demanded Mrs. Munsterberg.

But Dr. Munsterberg wasn’t listening anymore. He had walked to the window and was searching the grounds outside for any hint of metal gleaming in the dark. Everyone in New York City had lived alongside Morningstarr Machines for years, but Dr. Munsterberg had never seen machines so small. And now he had to wonder how very small the Morningstarrs could make their machines.

Or, he thought, how very big.

New York City

Present Day

CHAPTER ONE

Tess

There are cats, and there are Cats.

Your typical lowercase cat is fascinating enough. Alternately elegant and ridiculous, liquid and solid, here and gone. But Cats, well, Cats are more. Slinkier and sassier, bigger and bendier, a concentration of Catness, a multiplicity of cats in a single body. A Cat is every cat, and no cat at all.

If you asked Tess Biedermann, her cat Nine was such a Cat.

Not that Tess was biased or anything.

“It’s science,” she said.

“I wish science had given Nine some flashlight eyes,” said Tess’s friend Jaime Cruz. “It’s dark as deep space in here.”

Tess, Jaime, and Tess’s brother, Theo, were standing inside a building on West 73rd Street in Manhattan. This nondescript structure had once stood next to their old apartment building, an original Morningstarr building, managed by Jaime’s grandmother. It was the building they’d all called home.

A home they loved. A home they’d hoped to save. A home they’d helped to destroy.

They were trying hard not to dwell on that last part.

Outside, it was a bright and steamy August day, but here, inside the closed door, a door that had been hidden from the world for over a century and a half, the cool air was thick with dust, the darkness impenetrable. It was the third time they’d tried to explore this place. The first time, they were so disappointed not to find the treasure they were seeking right behind the door, they’d turned around and marched out again. The second time, they’d been stopped outside by an overly ambitious security guard who told them he’d have them arrested if he ever saw them again.