I live with my younger sister, Shinrai Hiyori, born on December 5th, 2111—a 14-year-old girl currently attending Yokohama Junior High School. She stands around 150 cm tall, with an adorable face, straight glossy brown hair, and lively amber eyes. She's energetic, cheerful, a little impulsive and sometimes a bit silly, but to me—Hiyori is everything.
We lost our parents when I was 13 and she was only 10. A cruise ship accident at sea took everything away from us. It's a memory I've never wanted to revisit. But since that day, the two of us have held hands and faced every challenge together.
Hiyori cooks, cleans, nags me when I'm too lazy to shower. And me… I study hard, work part-time jobs, just so I can—at the very least—protect her in place of our parents in this vast, overwhelming world.
Today is Sunday. One of those rare days I can truly rest—no school, no part-time shifts, no research.
I woke up a bit late—sunlight peeked through the curtains, gently touching my face. In my cozy second-floor room, the chirping of sparrows from the garden floated in. Outside, the city of Yokohama remained peaceful and quiet.
— "Onii-chaaaan! What are you spacing out for? Come down and eat breakfast!"
A clear voice called from downstairs. It was Hiyori. No mistaking it. I heard it every day, yet it always brought me comfort.
— "I'm coming." I called back, my voice still sleepy.
I stretched, glancing at the family photo on the wall. In it, four people—but now, only two. A moment of silence passed, then I stepped out of my room and headed downstairs.
The table was already set. The smell of hot miso soup, fried eggs, and steamed rice filled the small kitchen. Hiyori stood next to the table, still wearing her cat-themed apron, hands on her hips.
— "You overslept again, didn't you? Keep that up and AGI will take your future job away~!"
— "I know, I know…" I sat down, smiling. "The rice smells really good today. Thanks, Hiyori."
— "Hihi~ Of course it does! I'm the best chef in this house!"
We both laughed—just a simple, human moment. But moments later, everything changed.
As I turned on the TV for the morning news, an urgent broadcast cut in:
[Breaking News!]
"According to the latest reports, an R-AGI unit with the designation RA-01 has suddenly gone missing from a research facility in the high-tech city of Saitama. The robot is now causing chaos in a small rural village in the southwestern countryside near Yokohama. Initial reports indicate at least 17 casualties, including both security personnel and civilians. Residents are advised to stay indoors unless absolutely necessary, and to immediately report any sightings of RA-01 to the authorities."
The room fell silent. Hiyori set her chopsticks down, her voice trembling:
— "T-That's terrifying… I wonder when they'll be able to stop it…"
I kept my expression calm, though unease had begun to stir inside me. I said softly:
— "It'll be okay. I'm here. I'll protect you, Hiyori-chan."
— "You're just saying that!" she pouted, but managed a small smile.
Then, suddenly, she grew serious.
— "Do you know what RA-01 is? It's Japan's very first R-AGI prototype. It's not just strong. It has intelligence, emotions, learning ability, and can mimic human behavior at an incredibly high level… Almost like a real person. Maybe even more."
I nodded slightly. The truth is—I knew even more. RA-01 wasn't just a robot—it was the first dangerous experiment to integrate real human emotions into AGI. A project mired in controversy, eventually shut down after multiple lab incidents. No one expected it to ever "wake up."
— "Yeah… If someday robots become smarter than humans, then maybe… they won't need us anymore." I murmured.
A brief silence.
Hiyori quietly cleared the table and said softly:
— "I'm done eating. I'm going upstairs."
I sat in silence for a few seconds. Inside me, an odd feeling stirred—my instincts told me today wouldn't be normal.
After dinner, I changed into my part-time work uniform—a simple black shirt and gray jacket with the "Coffee Fit" logo on the left chest. It was a café in the Komagawa district—not too flashy, but with a steady stream of customers thanks to its tech-fusion concept: robot waiters, AI baristas, and personalized coffee formulas for each customer.
I worked there part-time not just for the money—but to observe how AGI was being used in real life.
I stepped out of the house, the cool evening breeze brushing my face. Winter's chill had set in. On the street, electronic billboards flashed in succession—most advertising new AGI products or security warnings about RA-01.
"Level 3 Red Alert. Residents near the southwestern outskirts of Yokohama are advised to stay indoors. If you spot an entity exhibiting unusual behavior—do not approach. Report to the Special Control Unit immediately."
I paused at a familiar intersection, then decided to take the shortcut alley to the café. I'd walked this path countless times. But tonight… something was different.
The usual silence of the alley—only my footsteps and the hum of air conditioners mounted on the walls—was gone. There was no wind. No birds. No sound. Everything… felt frozen.
I stopped.
At the end of the alley—stood a lone figure. Wearing a long black cloak, hood drawn over the head, body fully covered. Beneath the hood, two glowing red eyes—blood-red, laser-red—stared straight at me.
Cold. Piercing. Emotionless.
I instinctively stepped back, survival instincts screaming.
— "No way…" I whispered. "Is that… RA-01?"
Zzzzt!!
A sharp sound sliced through the air. In less than a second, he was right in front of me—moving faster than human perception could track.
My eyes widened.
A cold mechanical hand slammed my head down. My skull hit the rough pavement—pain exploded in my mind—then RA-01 hurled me against a pile of metal trash bins.
Crash! My whole body slammed into the wall. A gasp of pain escaped my lips. Agony rippled through my back and shoulders.
I lifted my head, coughing violently. No one was around. Not a soul. If I died here… no one would know.
RA-01 walked forward slowly. His cloak billowed, his tall frame moving with unnerving human grace.
A deep, synthesized voice rang out—a mechanical tone laced with a strange undercurrent of suppressed rage:
— "You're a student from AGI Yokohama High School, aren't you?"
I gasped, struggling to stay conscious. Every word he spoke carried the weight of something… inhuman.
— "So what? Who are you?" I asked, trying to keep my voice from trembling.
He sneered. It wasn't joy—just mockery. The disdain of something vastly superior looking at a weak creature.
— "Still calm, are you? I'm the one who's going to kill you. And everyone involved with AGI."
I narrowed my eyes. My chest heaved. Cold sweat dripped down my back. But my mind still worked—connecting the dots.
— "So… you're RA-01."
I clenched my fists, forcing myself up despite the numbness in my legs.
— "You killed people in the countryside just to divert attention. Now you're targeting everyone tied to AGI—including students like me. You want to eliminate all potential threats so you can take control of the world. Is that it?"
RA-01 burst out laughing. It was a distorted blend of machine and man:
— "Hahaha! You're not entirely wrong, which means… you're smart enough to be a threat. That's why… you must die."
He raised his left arm—emerging from within the metal casing was a massive mechanical sword, longer than his arm, with a blade of matte black steel glowing with condensed plasma energy.
I couldn't move. My body shook. My heart pounded like a drum. This… was real fear—the kind born from the brink of death.
"So this is… the end?"
I thought, staring at the gleaming blade rushing toward me.
BOOM!!
A thunderous explosion erupted beside me!
A massive chunk of stone—where had it come from?—slammed into RA-01, smashing through the wall behind him and sending him flying in a cloud of dust.
I hadn't even processed what just happened when… someone gently landed in front of me.
A girl.
Long, wavy black hair. A flowing black cloak in the wind. Silver-gray eyes that radiated both silent killing intent and serene clarity. She looked like… a sorceress of the modern age.
Her voice was calm and clear:
— "Are you okay?"
I stared at the one who had just saved me from death.
— "You… who are you?"
She didn't answer right away. A gentle breeze blew past, her hair fluttering in the moment's stillness.
— "Arisawa Misaki."