The first time I saw her, the moon was an intruder. It was too large, too bright, and far too merciless for a place like Knockturn Alley. Usually, the jagged rooftops and overlapping drapes of the slums strangled the sky, reducing natural light to a few pathetic, grey threads. But that night, the silver poured through every gap in the architecture like molten lead, slicing the darkness into sharp-edged fragments that felt like they could draw blood.
I was sitting in the doorway of my shop, the wood still smelling of the lemon oil I'd used to scrub away the dead man's scent. I felt the change in the air before I heard a sound—a sudden, sharp tremor in the atmosphere, as if the alley itself was drawing a frightened breath. Then came the footsteps: fast, heavy, and dangerously uneven.
She rounded the bend with a desperate, lunging grace. She was tall, her dark hair clinging to a face pale with exhaustion and loss of blood. Her long coat was torn at the hem, dragging over the cobbles, and as she passed the reach of a flickering streetlamp, I saw the damage. Deep, jagged gashes across her stomach were weeping a dark, iridescent crimson that looked black under the oppressive moonlight. Her breathing was a study in forced control—the kind of breathing a person does when they are trying to keep their own intestines from sliding out of their body.
Our eyes locked. Hers were wide, amber-flecked, and burning with a frantic intelligence.
"Move," she rasped. Her voice was a jagged shard of glass, strained to the breaking point.
I didn't move. I didn't even stand. I simply watched as a second presence emerged from the silver haze at the far end of the alley. This one didn't run. It prowled. It moved with the unhurried, terrifying confidence of a beast that knows the cage is locked from the outside.
Fenrir Greyback.
Even in his human skin, he was a walking blasphemy. There was a feral musk about him—the smell of wet dog, iron-rich blood, and old, unwashed sweat. His grin was a crowded graveyard of yellowed teeth, and his eyes didn't look for a person; they looked for meat.
"Sister," Fenrir called out, his voice a low, vibrating growl that seemed to rattle the very vials on my shelves. "You can't outrun the moon. You know how she hates it when you play hard to catch."
The woman shifted, her weight trembling on her heels, but she instinctively placed herself between the monster and my doorway. I couldn't tell if it was an act of protection or a tactical error, but the gesture didn't escape me.
"You think these shadows will keep you?" Fenrir continued, cocking his head to the side. His eyes flicked over to me, landing on my small, seven-year-old frame with the casual indifference one might show a cockroach.
I stood up slowly, my hands resting near the leather satchel at my hip. "You're standing in front of my shop," I said. My voice was level, devoid of the high-pitched tremor of a child's fear. "That concerns me."
Fenrir paused, a flicker of genuine amusement breaking through his predatory focus. "The pup speaks. You don't understand what she is, little thing. You're inviting a plague into your house."
"I understand enough," I replied, my fingers brushing the cool glass of a vial. "I understand that blood on my doorstep is bad for business. And I understand that you're trespassing."
The moon climbed higher, and the air seemed to thicken, becoming heavy with the scent of ozone and incoming violence. The woman—Giselle, as I would soon learn—let out a hitched breath. She wasn't afraid of the man; she was terrified of the lunar cycle. She was fighting the pull of the silver light, her muscles bunching and twisting beneath her skin.
Fenrir stepped forward, the transition beginning to blur the edges of his humanity. "Run," she hissed at me.
I didn't argue. I wasn't a hero; I was a pragmatist. I grabbed her arm—her skin was burning hot, vibrating with a pre-transformative fever—and pulled her sharply down a narrow, pitch-black offshoot of the alley. Our boots struck the uneven stones in a frantic rhythm. Behind us, Fenrir followed. He didn't rush. He didn't need to. Every step he took was a mockery of our struggle. The moon favored him.
We reached a dead end—a wall of collapsed, soot-stained brick that had survived some ancient fire. There was nowhere left to run. Fenrir stepped into the mouth of the passage, silhouetted against the silver sky.
"You always did choose poorly, Giselle," he said, his voice dropping into a guttural register that was barely human. "Strays. Half-bloods. Weak, pathetic things. You'd rather die with a human runt than lead with your own blood."
I reached into my satchel, my movements economical and practiced. Fenrir's grin widened, seeing the small vials. "Glass, boy? You think a broken bottle will stop a King?"
"It's not just glass," I said.
I shattered the first vial against the cobbles between us.
A burst of brilliant, silver liquid erupted outward—then, it bloomed. This was Moonlace extract, concentrated far beyond any standard brewing manual's recommendations. It didn't just break; it detonated into a shimmering, heavy vapor. The mist caught the moonlight and warped it, bending the silver glow into a chaotic mess of fractured refractions. To a werewolf mid-shift, whose senses are dialed to a thousand, the visual feedback was like a physical blow to the retinas.
Fenrir recoiled, snarling as the vapor clung to his skin like freezing frost. Before he could recover, I smashed the second vial.
This one released a sharp, acrid scent that cut through the alley's filth like a scalpel—Wolfsbane, distilled and molecularly altered through a process I'd adapted from my old microbiology texts. It wasn't meant for ingestion. It was for dispersal. The vapor tangled with the Moonlace mist, creating a sensory dead zone. It didn't harm him, but it interfered with the chemical signals the moon was sending to his brain. It was a neurological jingle, a sensory static that threw his transformation into a stuttering halt.
Fenrir's posture broke. He clawed at his eyes, a sound of genuine, frustrated rage tearing from his throat. It was the sound of a predator who had suddenly lost the scent of the world.
"Go," I whispered.
We bolted. We slipped through the thinning edge of the silver haze, brushing past Fenrir's blurred, hulking outline before he could regain his bearings. My potions didn't have the power to kill a monster like him, but they had the precision to disrupt him. Fenrir Greyback valued blind, overwhelming frenzy; he was entirely unprepared for chemistry.
By the time the mist settled and the alley stopped screaming, we had vanished into the deeper, darker veins of Knockturn, moving through passages so narrow they felt like cracks in the world.
We stopped near a hidden storm drain. Giselle slumped against a damp stone wall, her breathing ragged but the frantic heat in her skin beginning to recede as the moon slipped behind a heavy bank of clouds. She looked at me, her amber eyes searching my face with a mixture of shock and dawning respect.
"You carry anti-werewolf vapor in your coat," she said, her voice a low rasp.
"I carry solutions," I replied, wiping a smudge of silver dust from my sleeve. "The world is full of problems. I prefer to be prepared."
"That wasn't standard Wolfsbane," she observed, her gaze lingering on my satchel. "It was... different. Sharper."
"It was modified," I said. "Standard recipes focus on the person. I focus on the catalyst."
She studied me for a long time, the silence stretching between us, no longer hostile or frantic. "Giselle Greyback," she said finally. "Unfortunately."
I inclined my head slightly. "The potioneer at the bend. That's not a name, but it's what people call me."
"It's sufficient," she said. She looked back toward the mouth of the alley, where the faint, distant growl of her brother echoed over the rooftops. It was a sound of promise, not defeat. "He won't forget tonight. He isn't the type to forgive a humiliation, especially from someone he can't even see over a counter."
"He won't enjoy repeating it," I answered.
Giselle hesitated, her hand pressing against the wounds on her stomach. "I know the forests," she said suddenly. "The old places. Places where the Ministry never goes and the light never reaches. I find things. Rare growth. Wolfsbane at its most potent, untouched by city soot. Moonlace that blooms before the frost. Night-blooming hellebore."
I didn't interrupt. I recognized the offer for what it was—a lifeline.
"I can supply you," she finished, her voice steadying. "Discreetly. I don't care for the shops in Diagon, and the merchants here are all cowards."
"And in return?" I asked.
"Proper Wolfsbane. Consistent. Controlled. Not the watered-down filth they sell to the desperate. I want to keep my mind, even when the moon is wrong."
I weighed the proposal. A werewolf who lived in the cracks of the world, who had the strength to resist Fenrir and the knowledge of the wild. A supplier who could provide ingredients that money couldn't buy in a traditional shop.
"A partnership," I said.
"Yes," she replied.
I extended my small, ink-stained hand. "Rare ingredients."
"Stability," she said, taking it. Her grip was firm, surprisingly warm despite the chill of the night.
The moon disappeared fully behind the clouds, and Knockturn Alley returned to its preferred, suffocating darkness. I felt the familiar weight of the world settle back into place, but it felt different now. Less like a prison, and more like a map.
"Ward your shop," Giselle said quietly before she stepped back into the shadows. "Fenrir enjoys breaking things that aren't his."
"I don't," I replied.
She paused at the edge of the darkness, a ghost of a smile touching her lips. "You didn't try to overpower him," she noted. "Most wizards would have tried a curse. They would have died."
"Predators expect force," I said, looking down at my hands. "They rarely expect chemistry."
With a final nod, she vanished into the dark. I stood alone in the silence for a moment, my mind already racing through the night's data. I was thinking about the refractive index of the Moonlace vapor, the way the Wolfsbane had interacted with the pre-transformative hormones, and how I could stabilize the formula for a wider dispersal area.
Fenrir Greyback would escalate. That was a mathematical certainty. But as I stepped back into my crooked shop and heard the lock click into place, I knew one thing for sure.
So would I.
I moved to the back of the shop, the wings beneath my skin humming with a silent, hidden power. The shelves would soon hold more than just common remedies. I had a supplier now. I had an ally who knew the dark as well as I knew the light. In Knockturn Alley, that was worth more than all the gold in Gringotts.
I picked up a quill and began to write. The business of survival had just become a war of attrition, and I intended to be the last one standing.