I live with my younger sister, Shinrai Hiyori, born on December 5th, 2111—a cheerful 14-year-old currently attending Yokohama Junior High School. She stands about 150 centimeters tall, with an adorable face, shoulder-length black hair with a hint of deep violet, styled in soft, wavy layers , and lively amber eyes that always seem to sparkle. 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 thirteen and she was only ten. A cruise ship accident at sea took everything from us. It's a memory I've never wanted to revisit. But from that day on, the two of us held hands and faced the world together.
Hiyori cooks, cleans, and scolds me when I forget to shower. As for me… I try to study hard, work part-time jobs—so that at the very least, I can protect her in place of our parents from this vast and unpredictable world.
Today is Sunday.One of those rare days when I can truly rest — no school, no part-time job, and no research to worry about.
I'm still lazily lying in bed, watching the soft orange-gold glow of the sunset filter through the window, casting warm, fading streaks across the ceiling. In this small, cozy room on the second floor, the evening air gently seeps in, bringing with it the quiet tenderness of a day drawing to a close.
Outside the window, the last birds are hurrying back to their nests. A light breeze stirs the trees in the garden, carrying with it the fresh scent of newly cut grass and the faint aroma of food drifting from a neighbor's kitchen somewhere nearby.
Right now, the city of Yokohama is at peace—no noise, no rush.Everything feels slower, as if the whole world is winding down in preparation for a warm dinner and a quiet evening ahead.
— "Onii-chaaaan! What are you spacing out for? Come down for breakfast already!"
A lively voice rang out from downstairs. It was Hiyori. No mistaking it. I hear it every day, but it always puts me at ease.
— "I'm coming," I called back, still groggy.
Stretching my arms, I glanced at the family photo on the wall. It showed the four of us—now, only two remain. A silent second passed before I stepped out of my room and headed downstairs.
The table was already set. The smell of hot miso soup, fried eggs, and fresh rice filled the cozy kitchen. Hiyori stood by the table, still wearing her cat-themed apron, hands on her hips.
— "You overslept again, didn't you? If you keep this up, AGI's going to steal all your future jobs~!"
— "I know, I know..." I smiled as I sat down. "Breakfast smells amazing. Thanks, Hiyori."
— "Hehe~ Of course it does! I'm the best chef in this house!"
We both laughed—just an ordinary laugh, so human and warm. But just minutes later, that peaceful morning would come to an abrupt end.
I had just turned on the TV to catch the morning news when a breaking report flashed on the screen:
[Emergency Bulletin!]"According to recent reports, R-AGI unit RA-01 has suddenly vanished from its research facility in the high-tech city of Saitama. The robot is now causing chaos in a small village in the southwestern countryside near Yokohama. Initial reports confirm at least 17 casualties, including both security personnel and civilians. Citizens are advised to stay indoors unless absolutely necessary. If you encounter RA-01, notify the authorities immediately."
The room fell silent. Hiyori set down her chopsticks, her voice trembling:
— "T-That's terrifying... Do you think they'll be able to stop it?"
I forced myself to remain calm, though anxiety had begun to stir within me. I replied gently:
— "It'll be fine. I'm here. I'll protect you, Hiyori-chan."
— "You're just saying that!" she pouted, trying to smile.
But then, her expression grew serious:
— "Do you know what RA-01 really is? It's Japan's first R-AGI prototype. It's not just powerful—it has intelligence, emotions, learning capabilities, and can mimic human behavior almost perfectly... It's practically human. Maybe even more."
I nodded slightly. In truth, I knew far more than that. RA-01 wasn't just a robot—it was the first dangerous experiment in integrating true emotions into AGI. A project that sparked fierce controversy, only to be abruptly shut down after a series of incidents in the lab. No one expected it to... come back to life.
— "Yeah... If robots become smarter than humans, maybe they'll realize they don't need us anymore." I muttered.
A quiet moment passed.
Hiyori stood and began clearing the table.
— "I'm done eating. I'll head upstairs."
I sat in silence for a few seconds. A strange sensation welled up inside me—an instinct whispering that today would be anything but normal.
That evening, I changed into my part-time uniform—a black shirt and a simple gray jacket with the "Coffee Fit" logo stitched on the chest. It's a café in the Komagawa district—not too busy, but it had a steady customer base thanks to its "tech-integrated" style: robot waiters, AI baristas, and coffee recipes personalized for each customer.
I worked there as a barista—not just for extra money, but to observe how AGI was being applied in everyday life.
I stepped outside, the night breeze brushing coolly against my face. Winter had fully arrived, its chill seeping into every corner. Along the streets, digital billboards flashed one after another—mostly AGI product ads or alerts related to the RA-01 incident.
"Level 3 Red Alert. All residents near the western outskirts of Yokohama are urged to stay indoors. If you witness an entity exhibiting abnormal behavior, do not engage. Notify the Special Control Unit immediately."
I paused at a familiar intersection, thinking for a moment, then decided to take the shortcut alley leading to the café. I'd walked this path countless times, but tonight... something felt off.
It was too quiet—usually, I could hear my own footsteps echo and the hum of air conditioners along the walls. But now, there was nothing. No wind. No birds. No sound.As if the entire alley had been... frozen.
I stopped.
At the end of the alley stood a lone figure—draped in a long black cloak, hooded, face hidden. But from beneath the hood, two glowing red eyes pierced the darkness—red like blood, like lasers.
That gaze locked onto me. Cold. Unfeeling.
I instinctively stepped back, every nerve in my body screaming danger.
— "No way..." I whispered. "That's... RA-01?"
Whizz!!
A sound like slicing air thundered past. In less than a second, it was right in front of me—moving faster than human senses could register.
My eyes widened.
A cold, mechanical arm slammed my head to the ground—the rough pavement scraping my skin—then RA-01 hurled me into the alley's dead end, crashing into a pile of metal trash bins.
Bang!My whole body slammed against the wall. A painful gasp escaped me. Agony spread through my back and shoulders.
I lifted my head, coughing. There was no one around. No witnesses.If I died here... no one would ever know.
RA-01 slowly approached. Its cloak fluttered with each step. Though tall, its build wasn't bulky—and its gait was strangely... human.
Then came its voice—deep and distorted, synthesized yet eerily restrained, almost like a person holding back rage:
— "You're a student at Yokohama AGI High School, aren't you?"
I gasped for breath, struggling to stay conscious. Each word carried the weight of something not human.
— "So what if I am? Who... are you?" I asked, though my hands were trembling.
He sneered—a cold smirk. Not of triumph, but of disdain for a feeble creature pretending to stand tall.
— "Still keeping your cool? I'm the one who's going to kill you. And everyone involved with AGI."
I narrowed my eyes, chest heaving. Cold sweat dripped down my back. But my mind remained sharp, connecting every piece.
— "So... you are RA-01."
I clenched my fists and forced myself up, though my legs still trembled.
— "You killed people in the countryside just to distract the media. Now you're targeting those linked to AGI—students like me. You're trying to erase every potential threat so you can take control of the world, aren't you?"
RA-01 laughed. The sound was like a distorted tape—half machine, half man.
— "Ha ha ha! Not entirely correct... but smart enough. That's why... you must die."
He raised his left arm. From beneath the metal casing, a long mechanical blade extended—longer than his arm, forged from dark-gray steel, glowing with a concentrated electromagnetic plasma.
I couldn't move. My body trembled. My heart pounded in my chest.This was true fear—death staring me in the face.
"So this is it…? The end?"I thought, eyes locked on the blade rushing toward me.
BOOM!!
A deafening explosion erupted beside me!
A massive rock—its source unknown—slammed into RA-01, smashing through the wall behind him and hurling him backward in a cloud of dust and debris.
Still stunned, I blinked as a figure gently landed in front of me.
A girl—with long, flowing black hair. A thin black cloak billowed around her in the wind. Her silver-gray eyes shimmered with both quiet wrath and solemn clarity. She radiated the aura of a... modern-day sorceress.
Her voice was calm, clear:
— "Are you hurt?"
I stared blankly at the person who had just saved me from death.
— "Who... are you?"
She didn't answer right away. A soft breeze passed between us, rustling her hair in the still silence of the moment.
— "Arisawa Misaki."