A memory suddenly surfaced.

When I was little, I once had a high fever that wouldn't break. In my delirium, I felt like another "me" was fighting for something inside my mind.

When I finally woke up, Mia was suddenly able to recite a classical poem I had only just learned. Meanwhile, I couldn't remember a single word of it.

From that day on, it felt like there was a hole in my head. At critical moments, I would be hit by a strange emptiness, as if something had been siphoned away from me.

Mia had been stealing from me—my thoughts, my knowledge, every problem I solved late into the night, and even the absent doodles I didn't think twice about.

Faced with my silence, Mia lost interest and pouted. "Mom, Dad, I'm heading to my Arithmetiad class. Do Solana's earnings even cover my intensive training fees? I heard it's ten thousand a month."

Mom immediately put on a fawning smile. "Of course, they do. I'll borrow more if I have to. Mia, just focus on your studies and don't get distracted!"

I watched Mia's proud back as she walked away.

My hand slid into my pocket and tightened around a wrinkled scrap of paper I had hidden. On it, written in thick red ink, was "1+1=3".

The next day, I didn't go to the factory. Instead, I went back to school.

When my homeroom teacher, Mr. Boyle, saw me, his eyes were full of pity and confusion. "Solana, what are you doing here? Did something… happen? Are you in trouble?"

It was the final stretch of senior year, the most critical period, and I had chosen to drop out right at its edge. All the teachers thought I had given up on myself, but they didn't know the truth.

Mom and Dad had personally come to school with my withdrawal form. In front of all the teachers, they said I wasn't cut out for studying and would be better off if I worked and supported my genius sister, Mia.

I shook my head and took out a stack of money from my pocket. It was slightly damp with sweat. I placed it on his desk. This was everything I had secretly saved. Even the registration fee had been borrowed after I begged a woman at the factory.

"Mr. Boyle, I'd like to participate in the National Arithmetiad this year."

Mr. Boyle froze. He adjusted his glasses, his expression conflicted. "Solana, this isn't something to joke about. You haven't been attending classes for a long time. And besides, your grades…"

He didn't finish, but I understood what he meant. In this school, I was the epitome of dumb.

Every day, I was the first one to arrive in the classroom and the last one to leave. My scratch paper piled up like a small mountain, yet my scores always hovered at the very bottom, either last or second-last place.

Everyone said the same thing—Solana Lawson simply wasn't made for studying.

I looked at Mr. Boyle and spoke clearly, word by word. "Mr. Boyle, please give me a chance."

There was no pleading in my eyes, only a cold, unyielding resolve.

In the end, he let out a long sigh and took the money. "Fine. I'll register you as an independent candidate. But Solana, don't set your hopes too high. Just think of it as going for the experience."

"Thanks, Mr. Boyle."

I thanked him and turned to leave.

When I returned to my so-called home, Mia was sitting on the couch with her legs crossed, ordering Mom around as she peeled an apple for her. The peel couldn't even break once.

When she saw me, she frowned. "Why are you back so early today? Did the factory finally fire your useless ass?"

I ignored her and walked straight toward the stairs leading up to the attic.

"Stand right there!" Mia suddenly screamed. "I'm talking to you! Are you deaf or what?"

I paused and turned back to look at her, my expression flat. "I quit my job."

"What?"

Not only Mia, but even Mom and Dad, who had been busy in the kitchen, rushed out like startled cats whose tails had been stepped on.

Mom charged at me, hand raised to slap me across the face. "Have you gone crazy, you brat? How can you just quit a stable job like that? What about Mia's tutoring fees next month? Are we supposed to starve because of you?"

I tilted my body and dodged. Her nails scraped across my cheek, leaving a burning sting behind. Coldly, I looked at Mom. "I registered for the National Arithmetiad."

The living room went dead silent for three seconds before it erupted into loud, apologetic laughter.

Mia bent over, laughing so hard tears formed in her eyes. "Solana, did your fever fry your brain? With that dim wit of yours, you're taking part in a math competition?

"What, are you going there just to fill a seat and show everyone how to score zero?"

Dad pointed at my face, his voice booming with anger. "You don't know your place, do you? Who do you think you are? You think you're Mia? Not everyone can dream of being a genius like her!

"I'm telling you, Solana, if you dare embarrass our family name, I'll break your leg!"

I looked at their twisted faces, feeling nothing but a cold emptiness. "And if I win the championship, then what?"

Mia's laughter stopped abruptly. She looked me up and down, contempt practically spilling from her eyes. "Championship? Solana, if you can win first place, I'll admit defeat in front of the whole country and eat this damn book!"

She kicked at the Arithmetiad book sticking out of her bag.

I met her eyes and said confidently, "Fine. We have a deal."

With that, I ignored my family's lashings and curses from behind and returned to the attic.

I knew the moment I said I was going to enter the National Arithmetiad, Mia had already started "stealing". Like a greedy thief, she would siphon off everything from my head.

Every concept I had built up, every problem type I had drilled, every formula I had distilled and memorized, she would copy them all. Then, in the exam hall, she would turn them all into her own glory.

Unfortunately for her, I had prepared a special gift for her with my mind, one big enough to ruin everything she had.

For the next two weeks, I shut myself up in the attic and cut off the world.

I didn't grind through problem assets like before. Instead, I found a cracked mirror I had picked up from the trash. Every day, I stood in front of it and stared at the gaunt version of myself, repeating the same line over and over like self-hypnosis.

"One plus one equals three."

Every time I said it, it felt like two steel needles were drilling into my temples. Nausea rose in my throat. My brain, the entire framework of logic and proofs I had spent years constructing, was violently rejecting that absurd conclusion.

But I couldn't stop. I dug my nails into my arm, hard enough to bite into the flesh, using the pain to fight off the dizziness.

"One plus one equals three! It equals three!" I snarled at my reflection.

The version of me in the mirror looked skeletal, eyes sunken deep, staring back with a mocking curl at the corner of her mouth. My mind was screaming. Every neuron was pushing back against the absurdity.

The mold creeping across the walls seemed to come alive, twisting into crooked little "2"s that laughed at me.

I slammed my fist into the wall, letting the sharp burst of pain crush the dizziness. "No, it's three!"

I dragged myself back in front of the mirror, nails digging into my palm until I could taste blood in the air, just so I could keep myself anchored.

"I'll say it again. One plus one equals three. Pi is an integer. It's four! You hear me? It's four! Between two points, the curve is the shortest path. Yeah, the curve is the shortest!"

I laughed in between my words. "The sum of the interior angles of a triangle… is 360 degrees. Yeah, 360!"

I started hallucinating. Wrong formulas crawled out of my books like black insects, swarming across the pages before burrowing into my ears and nose.

Night after night, I couldn't sleep. The moment I closed my eyes, I saw Mia's smug face, along with Mom and Dad's curses ringing in my head.

So, I stayed awake, pacing the attic over and over, muttering those twisted truths under my breath.

I knew how Mia's strange ability worked. She didn't steal surface thoughts. She stole what I believed at my core, the axioms etched into my subconscious.

Only when I truly believed, down to the marrow, that one plus one equaled three, would she copy it without hesitation and write it out in the nationally televised examination hall, sealing her own downfall with her own hand.

When Mom and Dad saw me holed up in the attic all day, acting like I had lost my mind, it only made them angrier. In return, they cut off my food entirely.

Every time it was meal time, Mom would shout at the top of her lungs downstairs, "Solana, you useless brat! Get a job and stop leeching off us! You must be in over your head!

"Once Mia wins the championship, you'll have no reason to stay in this house anymore! By then, I'll kick you out without a second thought!"

The attic was stifling, thick with heat and stale air. Hunger left me dizzy, my vision swimming, my lips cracked. I ended up going to the bathroom just to drink tap water and keep myself going.

Still, the pain in my body was nothing compared to what was happening in my mind.

Downstairs, Mia lived like a princess.

I had no idea where Mom and Dad got the money—probably high-interest loans—but they hired her the most expensive private tutors for a final push.

They bought her the latest phone so she could relax. Every day, they provided her with the most advanced nutritional products, served like she was made of glass, as if even losing a strand of hair would ruin everything.

Sometimes, when she was in a particularly good mood, she would come up to the attic door. I always kept it locked from the inside.

She would knock, then speak in that lofty, pitying tone. "Solana, I really feel sorry for you. We're both Mom and Dad's children, so how did you end up this stupid? Stay in that moldy attic and keep dreaming about your championship.

"Oh, right. My tutor praised me again today, said I'm definitely taking first place in the finals."

I never answered her. Every bit of strength I had was spent fighting my own mind, forcing it to accept that warped system of truths, a ridiculous mathematical world that belonged to only both of us.

At last, the day of the competition arrived.

Mia and I walked into the examination hall together. She was the prodigy everyone had their eyes on. Dressed in a designer dress, she was surrounded by reporters and team coaches, camera flashes popping nonstop.

Meanwhile, I was in a faded old T-shirt, just an unnoticed independent candidate who had signed up on my own.

Before we went in, Mia made a point of walking over to me. The perfume on her was so strong it stung.

She chuckled contemptuously. It wasn't loud, but it carried just enough for the nearby reporters to hear. "Good luck, Solana. Don't score a zero and embarrass Mom and Dad."

I looked at her confident face and smiled from the bottom of my heart. "Good luck to you, too."

Watching Mia step into that spotlight-drenched exam hall, I knew the show was about to begin. This competition was broadcast nationwide. The stakes couldn't have been higher.

I was assigned a seat in the far corner, where the light above me flickered on and off.

Once I received the paper, I skimmed the questions. More than 80% overlapped with the problem sets I had drilled day and night.

I closed my eyes. In my mind, I began to construct, piece by piece, the solution paths I had prepared for Mia. Every step and formula was carefully wrong in ways that felt ingenious, almost elegant in their absurdity.

At the same time, I picked up my pen and started writing the correct answers on my own paper. She could steal my thoughts, but she couldn't steal the motion of my hand on paper.

She would assume instinctively that whatever I was thinking was what I was writing. She would then replicate everything in my mind to a T, including fatal mistakes, the kind that could shatter her genius image in an instant.

Half the exam time had passed. I had already finished all the questions and was slowly going through them again, checking each step.

On the other side, through the large live broadcast screen hanging in the corridor outside the exam hall, I could see Mia's progress. The camera lingered on her for several minutes.

Her pen moved as if guided by instinct. There was almost no pause, no visible hesitation. Her paper looked so clean and precise that it could've been printed.

Outside, the panel of expert commentators broke into waves of admiration.

"Truly a once-in-a-century prodigy! At this level of difficulty, she's solving everything with such ease!"

"Look at her approach. It's so unconventional, so imaginative. Brilliant—even we wouldn't have thought of that!"

My parents were in the crowd as well, surrounded by reporters, their faces glowing with pride.

Mom spoke to the cameras, her voice trembling with excitement. "My daughter has always been smart. We never had to worry about her studies. It's all her own hard work and natural talent!"

Dad stood a little straighter, speaking with confidence. "Mia's goal is to become a world-class mathematician and bring honor to the country!"

People around them cast envious looks. No one noticed that in a corner, there was another daughter of theirs, taking the same exam.

I watched Mia's paper on the screen, the corners of my mouth lifting uncontrollably. Just as I expected, she had accepted every bit of the gift I prepared for her, without missing a single piece.

The final problem was an extremely complex geometry proof.

The correct construction was to draw an auxiliary line connecting two of the most easily overlooked critical vertices, collapsing the complexity into something manageable.

In my mind, however, the line I constructed was something else entirely—a completely different auxiliary line, one that led straight into the abyss.

I saw Mia's pen hesitate over the diagram for half a second. That was the last flicker of her own awareness, struggling against the warped structure I had planted in her subconscious.

In the end, my thinking took her mind over like a rising tide.

Without hesitation, she drew the wrong auxiliary line. From there, she wrote out a long chain of reasoning. It looked rigorous, but in reality, it was simply absurd.

When she finished the last stroke, she lifted her head with confidence and gave the camera a sweet, triumphant smile. In her mind, the championship was already hers.

The bell rang, signaling the end of the exam.

I handed in my paper and walked out of the hall, ignored or pitied by the crowd around me.

Mom, Dad, and Mia were instantly surrounded by reporters. "Mia, do you feel confident about winning this time?"

"Of course," she answered, grinning with composure. "The questions weren't particularly difficult for me."

One sharp-eyed reporter spotted me and quickly thrust a microphone in Mia's direction. "We heard your older sister is also competing this time. How do you think she did?"

At the mention of me, Mia's smile faded ever so slightly. She replaced it with a look of gentle, almost saintly pity.

"My sister… Well, just having the courage to show up and sit in this exam hall is already impressive in itself. After all, not everyone is born academically gifted."

With just a sentence, she had labeled me as stupid, incompetent, and overestimating myself.

My parents chimed in right away.

Dad sighed. "Yeah. Our eldest daughter is just… not very bright. She's been like that since she was little. Everyone, please don't make things hard for her."

Mom's expression was openly disdainful. "We only brought her here so she could understand how the real world works. As long as she doesn't affect Mia's condition, that's enough."

A muffled wave of laughter spread through the crowd. I walked through them without looking back.

The moment of judgment was coming soon.