The walk to my car was a masterclass in suppressed panic.
Every set of footsteps behind me on the asphalt sounded like a countdown. Every squeal of a school bus brake was a scream I was holding behind my teeth. I kept my hand deep in my pocket, fingers curled around the grip of the snub-nosed .38. It was a cold, comforting weight, the only thing in my universe that still obeyed the laws of physics.
I didn't look back. Looking back is for people who believe they can change the past. I'm a mathematician; I know that once you subtract a value, it's gone. You're only left with the remainder.
I reached my Volvo—a sensible, silver sedan, the ultimate camouflage for a man who didn't want to be noticed—and got inside. I locked the doors immediately. The click of the central locking system was the first beat of silence I'd had all day.
I sat there for a moment, staring at the steering wheel. My hands were shaking. I forced them onto the ten and two positions. I gripped the leather until my knuckles turned the color of the chalk dust still embedded in my cuticles.
Calculate the variables, Elias.
Variable A: Leo Miller. Seventeen. Too smart for remedial math. Access to information that should have been buried at the bottom of Blackwood Lake.
Variable B: The Father. Apparently a resident of that town. A man who saw a genius where the police saw a tragedy.
Variable C: The Diagram. He knew the layout of my house.
I started the engine. The car hummed to life, a steady, mechanical vibration that usually calmed me. Not today. Today, it felt like the idling engine of that black sedan from three years ago.
I didn't go straight home. Going home was a predictable move, and predictable moves are how you lose the game. Instead, I drove to the public library three towns over. I needed a terminal that wasn't connected to the school's network. I needed to see what the "rest of the world" remembered about the night the math failed.
The library smelled of old paper and desperation. I found a computer in the corner, shielded by a stack of oversized geography books. My fingers flew over the keys.
Blackwood Lake. November 2022. Accident.
The results were the same as they'd always been. A single-car accident. Driver survived; passenger did not. No signs of foul play. The driver, a brilliant young actuary named Elias Thorne, had suffered a "neurological break" due to grief and disappeared from public life shortly after the settlement.
I scrolled deeper. I searched for "Miller" in the Blackwood Gazette archives from that year.
There it was.
Arthur Miller. Arrested for Witness Tampering. Case Dismissed.
I felt a cold prickle at the base of my spine. Arthur Miller hadn't been a drunk or a local gossip. He'd been a private investigator—a man paid to find things that people like me paid to hide. And he'd died in a "industrial accident" six months after the lake incident.
Leo wasn't just a debt collector. He was an inheritance.
I shut down the computer. My reflection in the darkened monitor looked hollowed out, the shadows under my eyes like ink blots. I wasn't the man in the newspaper anymore. That man was a genius who could calculate the probability of a heart attack to four decimal places. This man was a tired teacher who was being hunted by a ghost in a hoodie.
I drove home as the sun began to bleed out over the horizon, turning the sky a bruised, angry purple. My house was a small, modernist box of glass and cedar, tucked away at the end of a gravel road. It was designed to be a sanctuary of right angles and clean lines.
But as I pulled into the driveway, I saw it.
The front door was ajar. Only by an inch. Just enough to break the symmetry.
I didn't turn off the engine. I sat in the dark, the headlights cutting through the rising mist. My heart was a metronome set to double-time. I reached into my coat and pulled out the .38. I checked the cylinder. Five rounds. Five chances to keep the sum at zero.
I stepped out of the car, leaving the door open. The gravel crunched under my shoes like grinding teeth. I climbed the porch steps, my breath hitching in my chest.
I pushed the door open with the barrel of the gun.
The house was silent. Too silent. The air didn't move. I moved through the entryway, my back against the wall. I checked the kitchen—everything was in its place. The knives were lined up by size. The spices were alphabetized.
Then I reached the living room.
In the center of the hardwood floor, someone had used white tailor's chalk to draw a perfect circle. Inside the circle, they had placed a single object.
It was my old briefcase. The one from the lake. It was still stained with the dark, silt-heavy water of Blackwood, the leather cracked and warped.
I stood over it, the gun heavy in my hand. I knew what was inside. I didn't want to look, but the logic of the situation demanded it. I knelt, keeping my eyes on the darkened hallway, and flipped the latches.
They clicked. A sound like a trap snapping shut.
Inside, there were no documents. No money. There was only a single, heavy stone from the shore of the lake, and a note written on a piece of school-standard lined paper.
The denominator is two, Mr. Kwame. You, and me. I'm just waiting to see who's on top.
I stood up, the briefcase falling from my hands. I turned toward the hallway, the gun raised, my finger tightening on the trigger.
"Leo!" I screamed. My voice sounded thin, alien in my own home. "I know you're here! The math doesn't work this way! You can't just appear!"
A floorboard creaked behind me.
I spun around, but there was no one. Only the reflection of the flickering streetlamp in the glass wall of the living room.
I looked at the window, and my blood ran cold.
Written on the outside of the glass, in the condensation of the evening mist, was a formula.
(Greed- Mercy)dt =Death
I ran to the window, pressing my face against the glass. The woods beyond the lawn were a wall of black. I couldn't see him, but I could feel him. He was out there, calculating. He was measuring the distance between who I was and who I pretended to be.
I backed away, tripping over the briefcase. I fell, the gun skittering across the floor. I scrambled for it, my fingers scratching at the wood.
I realized then that Leo Miller didn't want to kill me. Not yet. He wanted to solve me. He wanted to break me down into my prime factors until there was nothing left but the raw, ugly truth of what happened in that car.
I picked up the gun and retreated to the corner of the room, the only place where I could see both the door and the window. I sat there in the dark, the .38 heavy in my lap.
I started to count. I counted the seconds. I counted the beats of my heart. I counted the sins I had tried to erase with a chalkboard eraser.
The night was long, and the math was just beginning.