Replaced by an AI Sister

My parents adopted an AI daughter.

The day they brought her home, I suddenly became the problem child.

My father called me a disappointment, and my mother decided I couldn't compare to Zya. My brother, Lucas, was the worst.

All you do is take things from us! Why can't you be useful for once? he'd snarl.

Heartbroken and furious, I once pushed Zya to the ground.

My mother's face went cold. She slapped me so hard my ears rang.

"Zya is your sister! If you were even half as obedient as she is, I wouldn't have these constant migraines!" she hissed.

"You're going to the Apex Behavioral Institute. You'll stay there until you learn how to be a submissive, grateful daughter!"

I was forced to swap lives with the AI daughter and was shipped off to the Institute.

Three years later, my parents and Lucas came to bring me home.

They called my name, but I remained as still as a statue.

The director smiled at them. "Mrs. Sterling, you have to say the activation phrase. Subject 1314 won't respond without it."

"Activate, Subject 1314."

My mother's voice was hesitant. She didn't seem to understand what she was saying; she was just mimicking the director.

My eyes lit up instantly. Like a screen that had been on standby for years, I finally received a signal.

I stood up from the chair, my hands resting naturally at my sides, my back perfectly straight.

"System activated. Please provide instructions."

My mother froze. Behind her, the director's voice rang out.

"Mrs. Sterling, our school designed a specialized system to better educate our students. A student requires an activation command to be awakened."

"With this command, she will never defy your will again!" the director added proudly.

My mother looked enlightened. Lucas pushed past her, a mischievous glint in his eyes.

He is five years older than me and had spent my entire childhood trying to make me cry.

Back then, I would chase him around the house until Mom yelled at both of us.

"1314, bark like a dog for me," Lucas commanded.

The moment the words left his mouth, I tucked in my neck, stuck out my tongue, and barked loudly.

Lucas burst into laughter and turned to our parents.

"Nora finally learned her place! She used to complain for hours about piano practice, but now she'll bark on command."

My parents nodded. It was clear they were incredibly satisfied with my performance.

On the drive home, my mother tried to make small talk.

"Nora, how was your life at the Institute these past three years?"

I didn't answer. She hadn't used the command "Answer."

"Nora?" she raised her voice.

I finally spoke, my voice as flat as a GPS navigation system.

"Interrogative sentences are not valid commands. If you require a response, please use the imperative form."

The air in the car turned to ice.

My mother's voice caught in her throat. After a long silence, she managed to say, "Answer."

"Life at the Institute was productive and meaningful. I completed core courses in Emotional Control, Absolute Obedience, and Rational Thinking."

"I graduated with honors. My instructor evaluated me as the 'Most Successful Transformation Case of the Year.'"

I recited the words perfectly. There was no pitch, no rhythm, no soulDjust a product manual being read aloud.

The backseat was silent for a long time.

Lucas whispered, "She's just like Zya now"

I kept my eyes fixed forward, expressionless.

The city outside was a blur. The buildings, the bridges, and the billboards were all different from what I remembered.

At the Institute, time was broken down into units of commands.

A day was no different from a month.

The only way I could tell time was passing was by the tally marks I scratched onto the walls of the Silent Room.

Eventually, I even forgot how to write my own name. When the car pulled into the driveway, it was almost dark.

Zya was standing at the front door. Her hands were folded in front of her, and her lips were curled into a perfect, standard smile.

Exactly six teeth showing. Just like three years ago.

Back then, Mom had knelt down to talk to her with a tenderness she never showed me.

"Zya, welcome home," she had said.

I had jumped off the sofa, wanting to see the new girl, but I tripped over something and fell flat on my face.

No one helped me up. They just told me I was too clumsy and loud.

Eventually, everyone hated me. I wasn't as obedient as Zya. I wasn't as thoughtful as Zya.

And that was why I was sent away.

"Welcome home, sister," Zya said. Her voice was sweet and melodic.

I didn't respond. She hadn't given me the command to "Answer."

My mother frowned. "Do you still hate Zya? I guess you still haven't learned. Speak to her!"

Receiving the command, I immediately flashed a smile.

"Acknowledged. Thank you."

Zya's smile didn't waver. My mother nodded in satisfaction.

At dinner, the family sat around the table.

Zya sat to Mom's right, Lucas to Dad's left, and I was placed at the very end.

The steam rose from the bowls, and the scent of rice filled the room, but my stomach didn't react.

At the Institute, eating was defined as "Energy Supplementation Behavior."

It had nothing to do with pleasure or hunger.

"Eat," Mom said casually.

I picked up my fork immediately.

Rice, beef, green peppers...

When Lucas saw me eating the peppers, his eyes widened.

"That's a first. You're actually eating green peppers? You used to be the pickiest eater on the planet."

I didn't answer. I just took another bite of the peppers.

The instructors said that preferences were "Sentimental Residue." They were signs of an incomplete transformation.

During my third month, I was locked in the Silent Room for forty-eight hours because I refused to eat peppers.

No light. No sound. No stimulation.

Only darkness.

When I came out, I ate the peppers.

Then I ate carrots, onions, and bitter melon.

I ate everything I used to hate.

Mom nodded. She always preferred children who weren't difficult.

A moment later, I reached for the bowl of peanuts.

I put a peanut in my mouth, chewed exactly fifteen times, and swallowed.

My father's eyes nearly popped out of his head. "She ate a peanut?"

"Nora, aren't you allergic? When you were a kid, one peanut made your throat close up! We had to rush you to the ER!"

Lucas dropped his fork. "The Institute can cure allergies too?"

I kept chewing silently.

At the Institute, a human doesn't need allergies.

The instructor had smeared peanut butter all over my arms.

The swelling, the blisters, the rotDit spread layer by layer.

"Allergies are a weakness of the flesh. Weakness can be trained into strength," they told me.

My skin rotted and regrew, over and over. The symptoms still appeared, but I was taught to ignore them.

My body began to shiver. My throat started to tighten, and my skin began to itch.

Horrible red hives began to break out across my face.

Lucas frowned. "Her face is getting red."

Mom leaned in to look, and her expression turned to horror.

"That's not blushing. That's an allergic reaction!"

"Nora, stop eating! You know you're allergic to peanuts!"

My fork froze mid-air.

I looked at my mother. My eyes were empty of emotion, and my voice was steady.

"Is that a command?"

My mother was stunned. I was already starting to wheeze, struggling for air.

Zya's sweet, gentle voice filled the room.

"The patient is experiencing an allergic reaction. Respiratory distress is at a moderate level. Hives cover twenty-three percent of the skin. I suggest immediate antihistamine treatment."

They snapped into action, frantically forcing allergy medication down my throat.

Once my breathing stabilized, the living room fell into a heavy silence.

Lucas's voice came from the sofa.

"Something is wrong with her."

"She used to cry, scream, and throw tantrums. She wasn't like this. She's... she's just like Zya!"

I didn't speak. He hadn't given the command to "Speak."

"Can you just be normal?"

His voice suddenly spiked. "Stop acting like Zya! we just wanted an obedient sister, not a machine!"

I looked at him. His face was full of anger and frustration.

I simply asked, "Please define 'Normal.'"

Lucas went pale. My parents looked equally disturbed.

My father called the Institute.

The person on the line explained that this was a standard reaction to "Deep Behavioral Correction" and that it would settle in a few days.

"Subject 1314 is our top student. She understands obedience better than any AI on the market."

"Don't worry. This is all part of the process."

My father hung up and repeated the words to my mother.

She nodded, and they both seemed to breathe a sigh of relief.

In the days that followed, I became the most useful tool in the house.

Mom told me to wash the dishes, and I got them cleaner than Zya ever did.

Dad told me to move the heavy planters, and I cleared the whole yard by myself.

Lucas told me to fetch his packages, and I ran faster than a stray dog.

Mom smiled and said, "Nora is actually more efficient than Zya now."

Everyone agreed.

Until the night Lucas forgot to shut me down.

Everyone went to bed.

I sat on the living room sofa from dusk until dawn.

When Mom came downstairs the next morning, she saw me sitting there in the exact same position she'd left me in.

She turned white as a sheet. Her coffee mug slipped from her hand and shattered on the floor.

A woman in a white coat came to the house.

She introduced herself as Dr. Thorne, a psychologist. Her voice was very soft.

"Hello, Nora."

I didn't speak.

My mother fidgeted beside me. "You have to give her a command, or she won't talk."

Dr. Thorne glanced at my mother and frowned.

"Tell me your name," Dr. Thorne said, using an imperative sentence.

"Subject 1314."

Dr. Thorne's pen paused on her notepad. "What is your birth name?"

"Nora Sterling. However, that is a legacy name. Institute regulations require graduates to use their serial number as their formal designation."

Dr. Thorne looked completely stunned.

The entire family looked sick.

They retreated into the study, speaking in hushed tones about things they thought I couldn't understand.

"Post-traumatic stress disorder... depersonalization... long-term therapy required..."

After that, the house felt strange. They started acting as if I were made of glass.

On Zya's birthday, they made a difficult decision.

They were going to send Zya away.

This was to be her last birthday with us.

The living room was filled with balloons, and a two-tiered cake sat on the table.

Zya walked over to me, her usual gentle self.

"Happy birthday, sister."

I blinked. Something in my brain seemed to loosen.

Today was my birthday, too.

No one remembered.

Three years ago today, I was shoved into a car and sent to that Institute.

Before I left, I begged my mother to let me have a piece of cake first.

She told me I could have it when I learned how to be a good girl.

I had learned.

But I still hadn't tasted the cake.

Zya suddenly smiled at me.

"Sister, the definition of 'normal' is pushing down people you don't like."

"Go ahead. Push me. Just like you did three years ago."

I looked at her. There was something flickering in her eyesDsomething that wasn't gentle at all.

But she had given me a definition for "Normal."

I placed my hands on her shoulders. I hadn't even pushed her yet when she collapsed.

Her skirt flared out on the floor like a dying flower.

The front door swung open.

Lucas stood there with a tray of fruit. He screamed at me.

"Nora! What the hell are you doing!"

The fruit tray hit the floor, berries rolling everywhere.

Zya sat on the ground, her eyes brimming with tears.

"Sister, why did you push me?"

"I thought you didn't hate me anymore. Why did you do it again?"

I didn't speak. She was faking.

I knew she was faking. Her tears were programmed simulations; her trembling was an algorithmic output.

Mom rushed over, her face shifting from shock to pure rage in seconds.

"What is wrong with you! Why would you push Zya!"

"She told me to."

"Liar!" Zya sobbed. "Why would I ever ask for that? I just wanted to wish my sister a happy birthday..."

Lucas knelt down to help Zya up. He was so gentle, as if she were a piece of fine china.

He looked up at me with eyes full of disappointment.

"You haven't changed at all."

"You spent three years at that place, came back acting like a saint, but the moment we turn our backs, you show your true colors."

"I knew it. You can't fix trash. You've always been jealous of Zya."

Mom's eyes were red, but not for me.

It was fury.

"And to think we were talking about being better to you."

"I was actually feeling guilty for sending you there. We were planning how to make it up to you."

She stepped closer, poking her finger into my chest.

"And this is what we get? You're still that vicious child. You still can't stand Zya. You faked it for three years. You fooled us all."

I opened my mouth. I wanted to say I wasn't faking. The Institute made me this way.

You sent me there.

But I couldn't say it. There was no command.

"Say something!" Mom screamed.

"I have not received the command to 'Speak.'"

Mom's face turned bright red.

Zya whimpered in her arms.

"Just go die," Lucas snapped suddenly.

The room went silent for a heartbeat.

"What did you say?" Dad frowned.

Lucas's voice was loud enough to rattle the windows. "I said she should just go die!"

"She follows every command, right? She's so obedient, right? Then let her go die! At least we'd have some peace!"

As soon as he said it, Zya collapsed to the floor.

Her body began to twitch. Her eyes rolled back, and white foam began to leak from her mouth.

"Zya! Zya, what's happening!" Mom shrieked.

Mom held her head, Dad tried to revive her, and Lucas scrambled for his phone to call 911.

They were all surrounding her. No one looked at me.

I turned away and looked at the garden below.

I stood in the middle of the room, watching Zya twitch and my family panic.

No one saw me.

"Command received. Terminating life."

No one heard me.

They were too busy crying over Zya.

I walked slowly toward the balcony.

The night air was cold against my skin.

"Nora!"

Lucas was the first to see me.

His voice was high and sharp. His phone slipped from his hand, clattering on the floor.

Mom turned around, the color draining from her face instantly.

"Nora! What are you doing!"

I gave her a small smile and executed the command without a second thought.