Next door, into the Museum of Magical History,” Oona finished.

She pushed aside what felt like some kind of heavy fabric and stood, smoothing out her dress. Deacon hopped into the room before fluttering to the corner of a large wooden desk.

“I do believe we are in the curator’s office,” Deacon observed.

“Yes, we are,” said Oona. “We are in the basement. The steps in front of the museum rise up so high that the basement is actually on the same level as the street … and, more important, the same level as the showroom next door.”

An ever-burning lamp glowed dimly on the desk, its enchanted flame giving the room a greenish tint. A long tapestry depicting an entire galaxy of stars and constellations took up the greater part of the wall behind the desk. It was from behind this tapestry that she and Deacon had emerged. The floor was polished stone. To the right of the desk stood a broken glass case, above which hung a small brass-plated plaque. The inscription read:

FAY MORS EXPUGNO AND FAY MORS MORTIS

MAGICAL MIND DAGGERS

FIRST EVER ACQUISITIONS OF THE MUSEUM

OF MAGICAL HISTORY

AUGUST 12, 1418

Oona moved closer to the room’s single door and examined the lock. “Look here. You see, the heavy-duty bolt has a latch on this side of the door, and can only be opened with a key on the other side. Once they took the daggers, the thief unlocked the door and then pushed it open to make sure that no one would go looking for how they actually got in. Everyone assumed that the thief came in through the open door.”

“So the thief entered and exited through the hole in Madame Iree’s wall,” Deacon said. “But how did they get into the showroom?”

“I think the answer to that has to do with the missing cobblestones out front,” Oona replied.

“How is that?” asked Deacon.

Oona didn’t answer, but instead she pulled aside the tapestry and crawled back through the hole into the showroom, Deacon following closely behind. They found Isadora standing where they had left her, arms crossed over her frilly pink dress, fingers drumming.

“Did you find the dresses?” she asked.

“Shh, Isadora,” Oona said, before removing her father’s magnifying glass from her dress pocket and beginning an examination of the floor.

“Don’t shush me!” Isadora scolded. Nevertheless, she remained sullenly silent as Oona conducted her investigation.

It has to be here somewhere, Oona thought. There must be a second hole. It’s the only way.

But after several minutes of searching the floor, she found nothing. Not even a single crack. She sat down beside Deacon on the edge of the platform, feeling quite unsure of her theory. She had been so certain that Sanora Crone had come in through the floor of the showroom and then broken through the wall in order to enter the museum.

She stared at the magnifying glass, thinking of her father, and wondering if he would have been disappointed in her. She wished he was there, beside her. Surely her father would have known what to look for. But he wasn’t, and he never would be. She bowed her head, running her fingers through her hair … and that was when she saw the faint scratch marks in the wood at her feet.

“There,” Oona said.

She brought the magnifying glass to the scratches along the bottom edge of the platform, and Deacon peered through.

“Scratches in the polished wood,” he said. “What does it mean?”

Oona hurriedly moved to the other side of the platform, planted her feet firmly against the floor, and pushed.

“Here is where Sanora got in!” she exclaimed.

The platform slid easily across the smooth wood, revealing the secret beneath. Deacon hopped excitedly from one foot to the other, staring down at the hole in the floor. The very top of a ladder could be seen descending into the darkness below.

Isadora looked from the hole in the floor to the hole in the wall. “I don’t understand. Why are there two holes?”

Oona began rubbing her hands together. Here at last was something she could explain. “Remember last night, Isadora, when you asked the inspector if it were possible for the daggers and the dresses to have been stolen by the same person?”

“Everyone looked at me like I was crazy,” Isadora replied, giving Oona a fiercely reproachful look.

Oona winced, realizing that, yes, the idea had seemed somewhat ludicrous at the time. “Well, it turns out, you were right.” Oona pointed to the hole in the floor. “Sanora must have tunneled her way beneath the shop and come up here, beneath the platform. Though I doubt she was alone. This is a big job. One small girl could not have done it alone. It’s my guess that she had some help from her fellow witches.”

Oona scratched at her head. How the witches had known to come up in that exact spot, so that the platform would cover the hole, she didn’t know. But she intended to find out.

Peering into the hole, she gulped. “Will you go down first, Deacon? Or shall I?”

“And why would I go in there?” Deacon squawked. “Now that we know how the thief got in, we simply need to tell the authorities.”

Oona gave Deacon an incredulous look.

“Well, all right,” he admitted, “perhaps Inspector White will muck everything up, but it’s better than you or I going in there … alone.”

Oona turned to Isadora, but the fine young lady put up her hands. “I’m not going down in there.”

“And besides,” Deacon said, “if Sanora did steal the daggers, then that means she still has possession of the second one: Fay Mors Mortis. The Faerie Death. You promised your uncle that you would not go snooping around deadly criminals.”

“I know what I promised, Deacon,” Oona said. “But if Sanora was the one who threw the dagger at Uncle Alexander, then she is the only one who knows the words to transform him back. Red Martin intends to stop the Dark Street pendulum at midnight if the Wizard does not show up to reclaim Pendulum House.” She pointed at the hole in the floor. “Sanora Crone could stay down there in Witch Hill for months, or even longer.”

“Witch Hill?” said Deacon.

“Yes. Don’t you see? There is a tunnel leading directly from this spot to the hill across the street.”

“But how did you know it would be here?” Deacon asked.

“It all came from seeing those missing cobblestones. When I dropped the inspector’s candy through the pothole, I did it to illustrate a point, which is that the witches have dug a tunnel beneath the street. That’s why the cobblestones have gone missing, as well as the earth beneath them. The witches must have dug the tunnel terribly close to the surface, and the ground has begun to fall away in certain spots, like where the carriage wheels travel the most. That is why the carriages keep getting stuck.”

“Hmm,” Deacon intoned, glancing toward the filthy black dress that hung from Oona’s shoulder. “I can see why she would want to steal the dresses, since her own is so very drab, but why would she wish to imprison your uncle?”

“Maybe she meant to kill him,” Oona said. “Maybe she didn’t know which dagger she was using. I don’t know. As to why she would wish to harm him at all … that is precisely what I intend to find out.”

Moving with a swift sort of confidence that she did not entirely feel, Oona snatched one of the fallen candles from the floor. She then dug a match from her pocket and struck it along the edge of the platform. Her face glowed as she lit the candle and took in a deep breath, as if preparing to plunge into deep waters. The lit match dropped from her fingers into the hole, winking out as it disappeared into the darkness.

“Miss Crate,” said Isadora, almost tentatively.

Oona glanced over her shoulder. Strangely enough, she thought she saw an expression of concern on Isadora’s face. It seemed quite out of place there.

“Do be careful,” Isadora said. “No one knows what those witches do down there.”

It was the concern in Isadora’s voice that set Oona’s nerves on edge more than anything else. She had a strange, albeit short-lived thought that perhaps Isadora wasn’t quite as bad as she had judged her to be. Maybe there was a scrap of kindness in the girl after all. But the thought died quickly away when Isadora added: “And if you find the dresses, try not to get them dirty when you bring them back. That hole looks filthy.”

Oona did not bother to respond, but instead she lowered herself into the hole in the floor, the burning candle held in one faintly trembling hand, and began her descent into the darkness below.

Deacon hopped to her shoulder, shaking his head from side to side. “Oh dear. Here we go.”