“And how will you tell them apart, after you have dumped them into the pan?”

This stumped her, but only briefly. “I will cook the smaller eggs first, set them on the plate meant for my mistress and then cook the larger eggs.”

“Very good,” I said. “It will not take long. Within seconds, he may complain of a burning sensation in his mouth. Be sure to serve the eggs as hot as you can so he does not know any better—perhaps underneath a gravy or pepper sauce. He will think he’s only burned his tongue with the heat. Soon after, he will feel nauseous, and he will most certainly want to lie down.” I leaned forward, making sure Eliza clearly understood what I was to say next. “I suggest you do not permit yourself to see him after this.”

“Because he will be dead, you mean,” she said, expressionless.

“Not immediately,” I explained. “In the hours after ingesting nux vomica, most victims suffer a rigid spine. They may arch backward, like their body has been strung into a bow. I have never seen it myself, but I have been told it is horrifying. Indeed, the cause of a lifetime of nightmares.” I leaned back into my chair, softening my gaze. “When he dies, of course, this rigidity will release. He will look much more peaceful then.”

“And later, if someone asks to inspect the kitchen or the pans?”

“They will find nothing,” I assured her.

“Because of the magick?”

Placing my hands in my lap, I shook my head. “Little Eliza, let me make it very clear—this is not magick. These are not spells and incantations. These are earthly things, as real as the smudge of dust there on your cheek.” I licked the pad of my thumb, bent forward and ran it across her cheek. Satisfied, I sat back in my chair. “Magick and disguise may achieve the same end, but I assure you, they are very different things.” A look of confusion crossed her face. “Do you know the meaning of disguise?” I added.

She shook her head, shrugged one shoulder.

I motioned to the hidden door through which Eliza had come. “When you came into the storage room this morning on the other side of where we sit now, did you know that I watched you from a tiny hole set into the wall?” I pointed to the entrance of my hidden room.

“No,” she said. “I had no idea you were back here. When I first came in and found it empty, I thought you would come in off the alley, behind me. I would very much like one of these hidden rooms in a house someday.”

I tilted my head toward her. “Well, if you have something to hide, you very well might need to build yourself a hidden room.”

“Has it been here always?”

“No. When I was a child and worked here with my mother, there was no need for this room. We did not have poisons back then.”

The girl frowned. “You have not always sold poisons?”

“Not always, no.” Though there was little sense in sharing the details with young Eliza, the admission unfurled a painful memory.

Twenty years ago, my mother developed a cough at the start of the week, a fever by midweek, and was dead by Sunday. Gone in the short span of six days. At the age of twenty-one, I had lost my only family, my only friend, my great teacher. My mother’s work had become my work, and our tinctures were all I knew about the world. I wished, at the time, that I had died with her.

I could hardly keep the shop afloat, such was the sea of grief pulling me under. I couldn’t call on my father, having never known him. Decades ago, as a boatman, he’d lived in London several months—just long enough to seduce my mother—before his crew set sail again. I had no siblings, few friends to speak of. The life of an apothecary is a strange, solitary one. The very nature of my mother’s business meant we spent more time in the companionship of potions than people. After she left me, I believed my heart had fractured, and I feared my mother’s legacy—and the shop—would also meet their demise.

But like an elixir splashed onto the very flame of my grief, a young, dark-haired man named Frederick entered my life. At the time, I’d thought the chance encounter a blessing; his presence began to cool and soften so much that had gone awry. He was a meat merchant, making quick work of the mess I’d accumulated since my mother’s death: debts I had not paid, dyes I had not inventoried, dues I had not collected. And even after the shop’s figures had been fixed, Frederick remained. He did not want to be apart from me, nor me from him.

Whereas I’d once thought myself skilled in only the intricacies of my apothecary shop, I soon realized my expertise in other techniques, the release between two bodies, a remedy that couldn’t be found in the vials lining my walls. In the weeks to follow, we fell terribly, wonderfully in love. My sea of grief grew shallower; I could breathe again, and I could envision the future—a future with Frederick.

I couldn’t have known that mere months after falling in love with him, I would dispense a fatal dose of rat poison to kill him.

The first betrayal. The first victim. The beginning of a stained legacy.

“The shop must not have been very amusing back then,” Eliza said, turning her head away as though disappointed. “No poisons, and no hidden room? Humph. Anyone should like a secret room.”

Though her innocence was enviable, she was too young to understand the curse of a once-loved place—hidden room or not—that had been marred by loss. “It is not about amusement, Eliza. It is about concealment. That is what it means to disguise something. Anyone can buy poison, but you cannot simply drop a pellet of it into one’s scrambled eggs, because the officials may find residue or the box of poison in the trash. No, it must be so cleverly disguised that it is untraceable. The poison is disguised in that egg just as my shop is disguised within the bowels of an old storage room. That way, anyone not meant to be here will undoubtedly turn around and leave. The storage room at the front is a measure of protection for me, you might say.”