The floor ramped upward, leading us past silent furnaces bearded with frost, into a large room clogged floor to ceiling and wall to wall with ice except for the tunnel we were in, which had been carved straight through the middle. The ice was thick but clear, and in some places I could see twenty or thirty feet into it with only a slight waver of distortion. The room appeared to be a reception area, with rows of straight-backed chairs facing a massive desk and some filing cabinets, all trapped inside tons of ice. Blue-filtered daylight shone from a row of unreachable windows, beyond which was the street, a smear of indistinct gray.

A hundred hollows could spend a week hacking at that ice and not reach us. If not for the tunnel entrance, this place would make a perfect fortress. Either that or a perfect prison.

On the walls hung dozens of clocks, their stilled hands pointed every which way. (To keep track of the time in different loops, maybe?) Above them, directional signs pointed the way to certain offices:

← UNDERSECRETARY OF TEMPORAL AFFAIRS

← CONSERVATOR OF GRAPHICAL RECORDS

NONSPECIFIC MATTERS OF URGENCY →

DEPT. OF OBFUSCATION AND DEFERMENT →

Through the door to the Temporal Affairs office, I saw a man trapped in the ice. He was frozen in a stooped posture, as if he’d been trying to dislodge his feet as ice overtook the rest of him. He’d been there a long time. I shuddered and looked away.

The tunnel came to an end at a fancy, balustraded staircase that was free of ice but awash in loose papers. A girl stood on one of the lower steps, and she watched our halting, slip-sliding approach without enthusiasm. She had long hair that was parted severely down the middle and fell all the way to her hips, small, round glasses she was constantly adjusting, and thin lips that looked like they’d never once curled into a smile.

“Althea!” Miss Wren said sharply. “You mustn’t wander off like that while the passage is open—anything at all might wander in here!”

“Yes, mistress,” the girl said, then cocked her head slightly.

“Who are they, mistress?”

“These are Miss Peregrine’s wards. The ones I was telling you about.”

“Have they brought any food with them? Or medicine? Or anything useful at all?” The girl spoke with excruciating slowness, her voice as wooden as her expression.

“No more questions until you’ve closed up,” Miss Wren said. “Quick now!”

“Yes, mistress,” the girl said, and with no apparent sense of urgency she ambled away down the tunnel, dragging her hands along the walls as she went.

“Apologies for that,” said Miss Wren. “Althea doesn’t mean to be obstinate; she’s just naturally mulish. But she keeps the wolves at bay, and we badly need her. We’ll wait here until she returns.”

Miss Wren sat on the bottom step, and as she lowered herself I could almost hear her old bones creaking. I didn’t know what she meant by keeps the wolves at bay, but there were too many other questions to be asked, so that one would have to wait.

“Miss Wren, how did you know who we are?” asked Emma. “We never said.”

“It’s an ymbryne’s business to know,” she replied. “I have watchers in the trees from here to the Irish Sea. And besides, you’re famous! There’s only one ymbryne whose wards were able to slip the corrupted’s grasp complete and entire, and that’s Miss Peregrine. But I’ve no idea how you made it this far without being captured—or how in peculiardom you found me!”

“A boy at the carnival directed us here,” said Enoch. He raised a hand level with his chin. “About yea big? Wearing a silly hat?”

“One of our lookouts,” said Miss Wren, nodding. “But how did you find him?”

“We caught one of your spy pigeons,” Emma said proudly, “and she led us to this loop.” (She left out the part about Miss Peregrine having killed it.)

“My pigeons!” Miss Wren exclaimed. “But how did you know about them? Much less catch one?”

Then Millard stepped forward. He had borrowed Horace’s disguising-room overcoat to keep from freezing, and though Miss Wren didn’t seem surprised to see a coat hovering in the air, she was astonished when the invisible boy wearing it said, “I deduced your birds’ location from the Tales of the Peculiar, but we first heard of them in your mountaintop menagerie, from a pretentious dog.”

“But no one knows the location of my menagerie!”

Miss Wren was now almost too astonished to speak, and since every answer we gave her only sparked more questions, we laid out our whole story for her, as quickly as we could, stretching all the way back to our escape from the island in those tiny, open boats.

“We nearly drowned!” said Olive.

“And got shot, and bombed, and eaten by hollows,” said Bronwyn.

“And run over by an underground train,” said Enoch.

“And squashed by a dresser,” said Horace, scowling at the telekinetic girl.

“We’ve traveled a long way across dangerous country,” Emma said, “all to find someone who could help Miss Peregrine. We were quite hoping that person would be you, Miss Wren.”

“Counting on it, really,” said Millard.

It took Miss Wren a few moments to find her voice, and when she did, it was gravelly with emotion. “You brave, wonderful children. You’re miracles, every one of you, and any ymbryne would be lucky to call you her wards.” She dabbed at a tear with the sleeve of her cloak. “I was so sorry to hear about what happened to your Miss Peregrine. I didn’t know her well, as I’m a retiring sort of person, but I promise you this: we’ll get her back. She and all our sisters!”

Get her back?

That’s when I realized Miss Peregrine was still hidden in the sack that Horace was carrying. Miss Wren hadn’t seen her yet!

Horace said, “Why, she’s right here!” and he put the sack down and untied it.

A moment later, Miss Peregrine came tottering out, dizzy after spending so long in the dark.

“By the Elderfolk!” Miss Wren exclaimed. “But … I heard she’d been taken by the wights!”

“She was taken,” Emma said, “and then we took her back!”

Miss Wren was so excited that she leapt up without her cane, and I had to steady her elbow to keep her from toppling over. “Alma, is that really you?” Miss Wren said breathlessly, and when she had her balance again she rushed over to scoop up Miss Peregrine. “Hullo, Alma? Is that you in there?”

“It’s her!” Emma said. “That’s Miss Peregrine!”

Miss Wren held the bird at arm’s length, turning her this way and that while Miss Peregrine squirmed. “Hum, hum, hum,” Miss Wren said under her breath, her eyes narrowing and lips drawing tight. “Something’s not right with your headmistress.”

“She got hurt,” said Olive. “Hurt on the inside.”

“She can’t turn human anymore,” said Emma.

Miss Wren nodded grimly, as if she’d already figured this out.

“How long’s it been?”

“Three days,” said Emma. “Ever since we stole her back from the wights.”

I said, “Your dog told us that if Miss Peregrine didn’t change back soon, she’d never be able to.”

“Yes,” Miss Wren said. “Addison was quite right about that.”

“He also said that the sort of help she needed was something only another ymbryne could give her,” said Emma.

“That’s right, too.”

“She’s changed,” said Bronwyn. “She isn’t herself anymore. We need the old Miss P back!”

“We can’t let this happen to her!” said Horace.

“So?” said Olive. “Can you turn her human now, please?”

We had surrounded Miss Wren and were pressing in on her, our desperation palpable.

Miss Wren put up her hands in a plea for quiet. “I wish it were that simple,” she said, “or so immediate. When an ymbryne remains a bird for too long, she becomes rigid, like a cold muscle. If you try and bend her back to shape too quickly, she’ll snap. She’s got to be massaged into her true form, delicately; worked and worked like clay. If I work with her through the night, I might have it done by morning.”

“If she has that long,” said Emma.

“Pray that she does,” said Miss Wren.

The long-haired girl returned, walking slowly toward us, dragging her hands along the tunnel walls. Everywhere they touched, layer upon layer of new ice formed. The tunnel behind her had already narrowed to just a few feet wide; soon it would be closed completely, and we’d be sealed in.

Miss Wren waved the girl over. “Althea! Run upstairs ahead of us and have the nurse prepare an examination room. I shall need all my medicinal remedies!”

“When you say remedies, do you mean your solutions, your infusions, or your suspensions?”

“All of them!” Miss Wren shouted. “And quickly—this is an emergency!”

Then I saw the girl notice Miss Peregrine, and her eyes widened a bit—the most I’d seen her react to anything—and she started up the stairs.

This time, she was running.

* * *

I held Miss Wren’s arm, steadying her as we climbed the stairs. The building had four stories, and we were heading for the top. Aside from the stairwell, that was the only part of the building still accessible; the other floors were all frozen shut, walls of ice clogging their rooms and hallways. We were, in effect, climbing through the hollowed center of a gigantic ice cube.

I glanced into some of the frozen rooms as we hurried past them. Bulging tongues of ice had broken doors off their hinges, and through their splintered jambs I could see evidence of a raid: kicked-over furniture, drawers torn open, snows of paper on the floor. A machine gun leaned against a desk, its owner frozen in flight. A peculiar slumped in a corner beneath a slash of bullet holes. Like the victims of Pompeii, arrested in ice rather than ash.

It was hard to believe one girl could have been responsible for all this. Apart from ymbrynes, Althea had to be one of the most powerful peculiars I’d ever met. I looked up in time to see her disappear around the landing above us, that endless mane of hair trailing behind her like a blurred afterimage.

I snapped an icicle off the wall. “She really did all this?” I said, turning it in my hand.

“She did indeed,” said Miss Wren, puffing beside me. “She is—or was, I should say—apprenticed to the minister of obfuscation and deferment, and was here performing her duties on the day the corrupted raided the building. At the time she knew little of her power other than that her hands radiated unnatural cold. To hear Althea tell it, her ability was the sort of thing that came in useful during hot summer days, but which she’d never thought of as a defense weapon until two hollows began devouring the minister before her very eyes. In mortal fear, she called upon a well of power previously unknown to her, froze the room—and the hollows—and then the entire building, all in the space of a few minutes.”

“Minutes!” Emma said. “I don’t believe it.”

“I rather wish I’d been here to witness it,” said Miss Wren, “though if I had, I likely would’ve been kidnapped along with the other ymbrynes who were present at the time—Miss Nightjar, Miss Finch, and Miss Crow.”

“Her ice didn’t stop the wights?” I asked.

“It stopped many of them,” said Miss Wren. “Several are still with us, I imagine, frozen in the building’s recesses. But despite their losses, the wights ultimately got what they came for. Before the entire building froze, they managed to secrete the ymbrynes out through the roof.” Miss Wren shook her head bitterly. “I swear on my life, one day I’ll personally escort all those that hurt my sisters to Hell.”

“All that power she has didn’t do any good at all, then,” said Enoch.

“Althea wasn’t able to save the ymbrynes,” Miss Wren said, “but she made this place, and that’s blessing enough. Without it we’d have no refuge anywhere. I’ve been using it as our base of operations for the past few days, bringing back survivors from raided loops as I come across them. This is our fortress, the only safe place for peculiars in all of London.”

“And what of your efforts, madam?” said Millard. “The dog said you came here to help your sisters. Have you had any luck?”

“No,” she said quietly. “My efforts have not been successful.”

“Maybe Jacob can help you, Miss Wren,” Olive said. “He’s very special.”

Miss Wren looked sideways at me. “Is that so? And what is your talent, young man?”

“I can see hollows,” I said, a little embarrassed. “And sense them.”

“And kill them, sometimes,” added Bronwyn. “If we hadn’t found you, Miss Wren, Jacob was going to help us slip past the hollows that guard the punishment loops, so that we could rescue one of the ymbrynes being held there. In fact, maybe he could help you …”

“That’s kind of you,” said Miss Wren, “but my sisters are not being held in the punishment loops, or anywhere near London, I’m sure.”

“They aren’t?” I said.

“No, and they never were. That business about the punishment loops was a ruse concocted to ensnare those ymbrynes whom the corrupted weren’t able to capture in their raids. Namely, myself. And it nearly worked. Like a fool, I flew right into their trap—the punishment loops are prisons, after all! I’m lucky to have escaped with only a few scars to show for it.”