The weekends were a different story. Hardly an hour passed without her company. Bicycling in the park (after an afternoon of instruction; I never got very good at it), picnics by the river when the weather warmed, hours in the library at the Society’s headquarters on the corner of Broadway and Twenty-second Street (when we could sneak away; Mrs. Bates took a dim vif all things monstrumological), and, of course, many hours at her great-uncle’s brownstone. Lilly adored Uncle Abram.

She had not given up her dream to become the first female monstrumologist. Indeed, she possessed an almost encyclopedic knowledge on the topic, from monstrumology’s colorful history to the even more colorful practitioners of the craft, from its catalogue of malevolent creatures to the intricacies of its Society’s governing charter. She knew more about monstrumology from studying on her own than I did after living two years with the greatest monstrumologist since Bacqueville de la Potherie, a rather embarrassing fact she delighted in pointing out at every opportunity.

“Well,” I said one Saturday afternoon while we sat among the dusty stacks on the fourth floor of the old opera house, my patience giving way, “maybe I’m just stupid.”

“I have often wondered.”

“Doing it isn’t the same as reading a book about it,” I shot back.

“The only thing the same as reading a book is… reading a book!” She laughed. “If you’d chosen books instead, you’d still have a finger.”

Like her mother, she had Abram von Helrung’s eyes, as blue as a mountain lake on a sunny autumn day. If you sank beneath the azure surface, you would drown for wanting to stay.

“Where did Dr. Warthrop go?” she asked suddenly. She popped this question at least four times a week. And I always gave the same answer, which was the truth:

“I don’t know.”

“What is he looking for?”

I had searched in the library for a picture of it. There was a very long entry in the Encyclopedia Bestia (cowritten by Warthrop), but no picture and no description of Typhoeus magnificum, except an extensive footnote detailing the various fanciful—that is, unverifiable—depictions of the Unseen One. It was a dragonlike creature, as von Helrung had mentioned, that took its victims “higher than the tallest mountain peak” before ripping them apart in its frenzy; it was a giant troll-like beast that flung pieces of its prey with such force that they fell from the sky miles from where their owners had lost them; it was an enormous wormlike invertebrate—a cousin of the Mongolian Death Worm, perhaps—that spat its venom with such velocity that it blew apart the human body, vaporizing it into a fine mist that came down again as the phenomenon called “red rain.”

The article mentioned the circumstances surrounding the discovery of the Lakshadweep nidus in 1851, the theories about the magnificum’s range (most monstrumologists agreed it was limited to the remote islands of the Indian Ocean and parts of Eastern Africa and Asia Minor, but that belief was based more on native traditions and stories than on hard scientific evidence), and the sad stories of the men who went looking for the Faceless One, the ones who returned empty-handed and the ones who did not return at all. Particularly poignant (and alarming) was the tale of Pierre Lebroque, a well-respected aberrant biologist—though somewhat of an iconoclast—who, after a five-month expedition in which no expense was spared (his party included five elephants, twenty-nine coolies, and a trunk-load of gold coins to bribe the local sultans), returned a raving lunatic. His family was forced into the painful decision of committing him to an asylum, where he lived out the remainder of his days in unrelieved torment, shouting the incessant refrain, “Nullité! Nullité! Nullité! That is all it is! Nothing, nothing, nothing!”

“He is searching for the Questing Beast,” I told her.

I suppose we cannot help it. We are hunters all. We are, for lack of a better word, monstrumologists. Our prey varies depending on our age, sex, interests, energy. Some hunt the simplest or silliest of things—the latest electronic device or the next promotion or the best-looking boy or girl in school. Others hunt fame, power, wealth. Some nobler souls chase the divine or knowledge or the betterment of humankind. In the winter of 1889, I stalked a human being. You might be thinking I mean Dr. Pellinore Warthrop. I do not. That person was me.

Go on, open it! the curator said. He wanted you to see.

Every night the same dream. The Locked Room. The old man jangling keys. And the box. The box and the boy and the stuck lid and the unseen thing moving inside the box and the old man scolding, Thickheaded boy! You can’t open it because you’re asleep!

And the thickheaded boy starting awake, sweating under warm covers in a cold room, teetering on the edge of it, das Ungeheuer, the center not holding, the me unwound, only the not-me awake now, echoing the cry of a madman, “Nullité! Nullité! Nullité! That is all it is! Nothing, nothing, nothing!”

Sometimes the woman down the hall heard him crying, and no matter the hour she rose from her bed and slipped on her robe and went down the hall to his room. She sat with him. “Hush now. Shhhh. It’s all right. It’s only a dream. Hush now. Shhh.” A mother’s refrain. She smelled of lilacs and rosewater, and sometimes he forgot and called her Mother. She did not correct him. “Hush now. Shhh. It’s only a dream.”

Or she would sing to him songs he’d never heard before, in languages he did not understand. Her voice was beautiful, a rich velvet curtain, a river over which the demons could not cross. He did not know a mortal voice could sound so heavenly.

“Do you mind my singing to you, William?”

“No, I don’t mind. I like the way it sounds.”

“When I was young girl around Lilly’s age, it was my great ambition to sing opera upon the professional stage.”

“Did you?”

“No, I never did.”

“Why not?”

“I married Mr. Bates.”

I was pursuing the one I had lost, the boy I was before I came to live with him. For a while—a vry long while—I thought I was hunting for the monstrumologist. He was, after all, the one who had dropped off the face of the earth.

I thought I saw him one night at the opera. Mrs. Bates took Lilly and me to a production of Wagner’s Das Rheingold, which had premiered at the Metropolitan Opera House the previous month.

“I hate the opera,” Lilly complained. “I don’t understand why Mother drags me to it.”

We were sitting in a private box high above the orchestra when I thought I spotted him in the crowd. I knew it was him. I did not question why the monstrumologist would be attending the opera—that did not matter. It was him. The doctor had come back! I started to stand; Lilly tugged me back into the chair.

“It’s Dr. Warthrop!” I whispered excitedly.

“Don’t be silly,” she whispered back. “And don’t say his name in front of Mother!”

I thought I saw him a second time, in Central Park, walking a Great Dane. When he drew close, I realized he was twenty years older and twenty pounds heavier.

Whenever I saw von Helrung, I asked the same question:

“Have you heard from the doctor?”

His answer on the seventeenth day was the same as his answer on the twenty-seventh:

“No, Will. Nothing yet.”

On the thirty-seventh day of my exile, after hearing those words again, No… nothing yet, I said to him, “Something is wrong. He should have written by now.”

“It could be that something is wrong—”

“Then, we must do something, Dr. von Helrung!”

“Or it could mean everything is very right. If Pellinore has picked up the trail of the magnificum, he would not take the time to write two words. You have served the man; you know this to be true.”

I did. When the fever of the hunt was upon him, nothing could distract him from his goal. But I was troubled.

“You have friends in England,” I said. “Can’t you ask them if they know where he’s gone?”

“Of course I can—and I will, if circumstances dictate, but not yet. Pellinore would never forgive me if I allowed that particular cat out of the bag.”

I returned on a blustery afternoon in early April to ask a special favor.

“I want to work in the Monstrumarium.”

“You want to work in the Monstrumarium!” The old monstrumologist was frowning. “What did Emily say?”

“It doesn’t matter what she says. She isn’t my guardian and she isn’t my mother. I don’t need her permission to do anything.”

“My dear little Will, I suspect the sun itself needs her permission to shine. Why do you want to work in the Monstrumarium?”

“Because I’m tired of sitting in the library. I’ve read so much, it feels as if my eyes are bleeding.”

“You have been reading?”

“You sound like Mrs. Bates. Yes, I do know how to read, Meister Abram. Well? I’m sure Professor Ainesworth could use some help.”

“Will, I don’t think Professor Ainesworth cares much for children.”

“I know. And he cares even less for me. That’s why I’m coming to you, Dr. von Helrung. You’re the president of the Society. He has to listen to you.”

“Listen, yes. Obey… Well, that’s something altogether different!”

His hope for success was not high, but he decided to humor me, and together we descended to the old man’s basement office. The meeting went well only in the sense of its outcome; the rest bordered on the disastrous. At one point I actually feared Adolphus might bash von Helrung’s head in. I do not need any help! He will sabotage my system! The Monstrumarium is no place for children! He will get himself hurt! He will get me hurt!

Von Helrung was patient. Von Helrung was gentle. Von Helrung was kind. He smiled and nodded and expressed his utmost respect for and admiration of the curator’s achievements, the finest collection of monstrumological relics in the world, and not merely that but the creation of the most unique cataloguing system in the Western hemisphere. He intended to propose at the next congress that a section of the Monstrumarium be named in his honor—the Adolphus Ainesworth Wing.

The professor was not mollified.

“Stupid! Too wordy! It should be the Ainesworth Wing—or better, the Ainesworth Collection.”

Von Helrung spread his hands apart as if to say, Whatever you like.

“I do not like children,” said the curator, scowling at me over his spectacles. “And I especially do not like children who meddle in dark places!” He pointed a crooked finger at von Helrung. “I don’t know what it is about this boy. Every time I look up, there he stands at the side of another monstrumologist. What happened to Warthrop?”

“He has been called away on urgent business.”

“Or he’s dead.”

Von Helrung blinked rapidly several times, then said, “Well, I am not sure. I don’t think so.”

“That’s the most urgent business there is, when you think about it,” Adolphus pronounced in my general direction. “Death. Sometimes I will be sitting here, just sitting here working away, and I will think about it, and then I will jump up from my chair and think, ‘Hurry Adolphus. Hurry, hurry! Do something!’”