I woke to a pain in my belly unlike any I had felt before. I placed my hands underneath my night shift and pressed my fingers into my skin. Beneath them, my skin felt warm and swollen, and I clenched my teeth as a dull ache began to spread itself wide.

It was not the same bellyache I might have had after too many sweets, or after spinning ’round in the summer garden with the fireflies back home. This ache was lower, like I needed to relieve myself. I rushed over to my chamber pot, but the heaviness still did not go away.

Oh, but what an important task lay ahead of me! The most important one my mistress had ever given me. It was more important than any dish I had scoured, or pudding I had baked, or envelope I had sealed. I could not disappoint her by saying I did not feel well and would like to stay in bed. Those excuses might have worked on the farm with my parents on a day when the horses needed brushing or the beans were ready to be plucked from their stalks. But not today, not in the towering brick house belonging to the Amwells.

Wiggling out of my night shift and walking to the washbasin, I resolved to ignore the discomfort. As I washed, as I tidied my garret room and as I stroked the nameless fat tabby cat who slept at the end of my cot, I whispered quietly to myself, as though saying it aloud made it more believable: “This morning, I will give him the poisonous eggs.”

The eggs. They remained nestled in the jar of ash, tucked into the pocket of my gown hanging near the bed. I removed the jar and pulled it to my chest, the coolness of the glass reaching me even through my nightgown. As I clutched the jar more tightly, my hands did not shake, not one bit.

I was a brave girl, at least about some things.

Two years ago at the age of ten, I rode with my mother from our small village of Swindon to the great, sprawling city of London. I had never been to London and had heard only rumors of its filth and its wealth. “An inhospitable place for people like us,” my father, a farmer, had always muttered.

But my mother disagreed. Privately, she would tell me of London’s bright colors—the golden steeples of the churches, the peacock blues of the gowns—and of the many peculiar shops and stores in the city. She described exotic animals wearing waistcoats, their handlers ushering them through the city streets, and market stands selling hot almond-cherry buns to a line of customers three dozen deep.

For a girl like me, surrounded by livestock and wild shrubs bearing little more than bitter fruit, such a place was unthinkable.