My idea of cozy and Mr. Morningside’s idea of it obviously did not align.

He led me into the circular rotunda outside his office and then to the right. I had never even looked there, as I assumed it was just the narrow area allowed by the spiral staircase. To any nonchalant passerby, it would appear unimportant, but now I saw that a curtain hung there. It was dark red and the bottom of it had been embroidered with silver thread in the pattern of locks and keyholes.

Mr. Morningside strode up to the curtain, the leather journal tucked under his arm. He swept aside the crimson fabric, revealing a hallway beyond. An impossible hallway. It looked to go on forever, dotted here and there with heavy iron-bound doors.

It looked, quite frankly, like a row of prison cells.

“But how . . . ,” I murmured, hesitating in front of the curtain. It was hard to see much, as the only light bleeding down the corridor came from the rotunda in which we stood.

“Only a fraction of my artifacts and sundries fit in the house itself,” Mr. Morningside explained, gesturing me forward. “A man of my taste and interests requires a good deal of storage.”

Cautiously, I took a few steps down the dark hallway, and just as they had when I first visited Mr. Morningside’s office, candleholders on either side of me flamed to life. Pale blue fire burned at our sides as we journeyed forward, and each new flicker made me jump. We passed several doors, and I began to count them out of curiosity.

“Here will do,” he said.

We had stopped six doors in, though clearly there were many, many more ahead of us, vanishing into the gloom that the blue glow of the candles could not reach. Mr. Morningside simply touched his open palm to the door, and a locking mechanism released. The hinges squealed as he pulled on the handle, and we were both met with a blast of stale, cold air.

“As a rule only I would be able to enter,” Mr. Morningside told me, holding the door while I stepped inside. “But that pin allows you to do more than just leave the grounds.”

“Then I could have come in here whenever I wanted?” I asked.

“Indeed. If you had known it existed,” he replied. “I wouldn’t let that knowledge go to your head, Louisa. As you discovered, there are dangers in this house, and I cannot promise that poking your nose into every corner and cranny will be good for your health.”

I thought at once of the large room upstairs, and the dark book that waited there, guarded by the shadowy Residents. My fingertips tingled at the memory, still burned from where I had touched the book, a touch that should have killed me but instead left only a permanent mark. That had been luck, really, and though I might never lose my inquisitiveness, it would be better to temper that curiosity with care. Accordingly, I took only a shallow step into the chamber, allowing Mr. Morningside to close the door behind us and stride into the unlit room.

He disappeared into the heavy swaths of shadow, and then I heard a crackle and a fireplace to my left filled with bright sapphire flames. The chill in the air lifted, and as Mr. Morningside made his way back to me, the candelabras on the wall blossomed with fire, too. The growing light revealed a large study, tidier than the upstairs library, with wall-to-wall shelves covered in all manner of antiques. I moved slowly along the wall toward the hearth, finding urns, daggers, dried flowers, a jar of teeth, and a tiny skull. Musical instruments I did not recognize, one like a flute but curved, and candles of every color, unlit but marked with runes and incantations. An unfinished portrait of four figures leaned against an ornate cupboard. The walls behind the shelves looked like those of a cave, as if this underground wonder had been scooped out of the earth ages ago. A charming collection of mismatched rugs was scattered across the bare earth floor, and the whole place smelled like cool, clean mud.

Mr. Morningside waited for me at a desk near the fireplace. A big, overstuffed chair was there, too, and he pulled it out, angling the fluffy seat toward me. He left the journal on the desk and crossed his arms, his foot tapping impatiently.

“I suppose you’re going to tell me not to touch anything in here,” I said, taking the proffered chair.

“Oh no, Louisa, by all means, please go digging through my personal belongings,” he said with a snort. “Rummage at your own risk, but do try to remember that time is of the essence. Wouldn’t you like to free your friends sooner rather than later?”

He tapped the leather journal and pushed off from the desk, crossing briskly to the door. “I’ll tell Mrs. Haylam to leave some dinner outside the door if you disappear for too long. There should be fresh parchment and quills in the desk, but don’t be shy if you need replacements. . . .”

“Wait,” I said, twisting in the chair. Mr. Morningside stopped in front of the door, his pointed chin turned toward me, one lock of black hair falling in front of his catlike eyes. “This place . . . The journal. Why do you trust me with these things? Poppy and Chijioke could help you. Or Mrs. Haylam. Why me?”

Laughing softly, he shook his head and brushed the hair out of his eyes. “Poppy and Chijioke are not Changelings. Mrs. Haylam has the eyesight of a vole. A vole with one eye, even. You are uniquely suited to this task, and I do so love efficiency.”

That wasn’t good enough, and perhaps he sensed it, because he did not immediately leave.

“You really can’t do this yourself?” I asked, waving my hand over the journal. “That doesn’t seem right; after all, you’re the—”

“I am many things, but I am not the right tool for the job,” he interrupted, and now his impatience had returned. Mr. Morningside’s mouth curled, but not pleasantly, and he set his gaze on me like an accusatory finger. I felt suddenly cold inside again, blood turning to ice as it had at the sight of Finch and Sparrow.

“Besides, I need to make this house appear as if it all runs smoothly. There are extra eyes on us now. You’re special, whether you appreciate that fact or not,” he said, a desperate edge to his voice. “Dark Fae are special. I did not ask the others because they are not Changelings. Perhaps it’s for the best that you’re going to meet your father one day. Maybe when you meet him you will understand how few of you there are left, how spectacular your gift truly is.”