Kaien Kurayami liked the safe measurements of ordinary things.
The glint of light on still water.
A sentence that meant the same no matter how you read it.
Those were the small certainties Kaien used to anchor himself.
Nozomi Haruka tugged at those anchors like loose threads.
Too loud, too curious, and she'd been that way since kindergarten.
Sota only cared about two things: snacks and sports. He had the kind of grin that stored other people's energy and lent it back at the worst possible jokes. He was the sort of friend who would ask a dumb question in class and make the teacher crack a smile. Kaien liked Sota for exactly that reason his trivialities made the rest of the world seem less urgent.
They loitered at the end of third period, packed bags slung, sunlight spearing the glass of classroom windows.
"Kaien!," he hissed just loud enough for Kaien to hear, "show me that cup trick again—the one where the pencil bends. I'm gonna blow Hana's mind on the train."
Kaien didn't even look up. "You mean the one that proves you'll stare at a glass of water for five minutes if someone says the word 'magic'?" He pulled a pen toward him, dropped it into a half-filled cup, and tapped the rim like a countdown.
Nozomi leaned in, her voice brushing his ear. "Show me too, Kaien. I need some kind of miracle before exams."
"It's refraction," he said, slow, like they were both kids again. "Light slows down in water, bends.The redirection can be caused by the wave's change in speed or by a change in the medium, so the pencil looks broken."
Sota squinted. "Still magic if you don't get it."
Nozomi laughed, nudging him. "Shut it, Sota."
The bell rang, and they stepped out together three small shapes slipping into the afternoon. Nozomi chattered about after-school club, Sota boasted about devouring an ungodly amount of convenience store curry, and Kaien let their voices fill the quiet spaces he liked to keep tidy.
At the back alley, their steps faltered. Nozomi ducked into the corner shop for candy. Sota said he'd be fine meeting his brother by the station. Without a word, they drifted into their usual separate paths.
"Text me when you get home, yeah?" Nozomi said, already turning toward her street.
"I will," Kaien replied. Her fingers brushed his sleeve for a moment—an ordinary touch that somehow stayed.
He took the shortcut as always—the paved strip behind the west wing that shaved minutes off the walk home. People used it because it was anonymous. It smelled of old detergent and heat in summer and faint oil in winter. Today the sun had a washed-out look, like paper left under a thin lamp.
He'd passed Sota by the vending machines earlier. They'd joked about which can of coffee was the most overpriced. An hour wasn't a meaningful distance, not a time that altered anything important.
At the maintenance door—where the alley narrowed and the shadows pooled—something was wrong.
A shape leaned against the wall. At first Kaien thought it was a lost man, slumped and embarrassed, waiting for help. Then his brain did the mapping that made faces from light and it refused the match.
The person's skin had the dull, green-slate of something that had been left in rain too long. The jacket clung in a way that read like old skin. One hand lay on the concrete and the knuckles had split; the fingernails were dull. The mouth hung slack in a way that wasn't sleeping. The eyes were a gloss.
It was Sota.
A cold thing moved inside Kaien. The kind that pushes you to the raw edge of thought—not yet words—only the animal knowledge that something had been violated.
He moved forward without meaning to, as if the body were a problem to be solved by proximity.
"Sota?" His voice sounded wrong in the alley. Small, sealed.
The body—Sota—turned. A smile spread, and the skin around the lips cracked with it. There was a sticky dark that had no business being that color on teeth.
Nozomi's voice had been in his ear minutes before; now the smell hit like a fist. Rot. A heavy, hot sweetness that made bile crawl up his throat.
Kaien's hands found his bag strap until his knuckles whitened. He needed to scream. He needed to run. Instead he blinked.
When his eyes opened the man was gone.
The maintenance door stood closed, unimaginative metal in the quiet. Puddles made neat rings on the pavement. The trash bin over by the corner had not moved. The alley smelled of nothing but old detergent.
Kaien's legs felt disconnected from his body. He stammered forward and pressed his palm flat to the wall where Sota had been leaning. Cold. Dry. Concrete.
He heard a sound then—a shoe scuffling in the street behind the fence—and the ordinary noises shoved him into a new reality: he had seen something no one else seemed to have seen.
Nozomi's text slid into his pocket like a small accusation: U ok?
He thumbed a reply without thinking; his fingers moved with the same autopilot that had walked him down the shortcut. Yeah. Late. See you.
His reply was a lie that felt like cardboard in his mouth, brittle and unhelpful.
By the time he reached home, the smell had gone with the memory, but not the dread. The kitchen light burned gold against the evening. Airi his little sister peered from the doorway at the sound of the gate.
"Onii-chan!" she chirped, leaping forward with the kind of ferocious affection only an eight-year-old could afford. She wrapped herself around his leg like a vine claiming a fence post.
Airi had a way of being small and enormous at the same time. She loved everything Kaien did: the way he fixed broken toys, the way he read until his voice grew hoarse at bedtime, the way he made up silly songs and pretended to be a monster to scare her into hysterics.
She was also… possessive. Airi's brother-complex it was a soft, constant pressure. She wanted to be the only one who knew his secrets. She wanted, in her way, to be needed.
Tonight she clambered up and tried to plant a kiss on his cheek. Kaien stiffened, then obliged with something like a smile. "You waiting up for me?"
"Always." She pouted, eyes serious. "Don't stay late again, okay? What if monsters get you?"
He laughed once. It sounded like a thing not fully formed.
"I'll be fine." He told her. The words felt like they were stitched from old fabric, familiar and threadbare.
Dinner was simple: miso, rice, a bit of grilled fish. Their mother watched them with that soft tiredness parents wearlike a blanket passed to cover the holes you don't want your children to see. Kaien ate because he should. He listened to Airi narrate her day in the kind of breathless sequence only children could manage: how she'd beat the boss in a game at recess, how she'd drawn a picture of their cat with blue stripes, how Nozomi's laugh sounded like wind chimes when she'd been happy.
He tried to answer. Nods, the occasional hollow laugh. The image of Sota's face—of that smile pulled too wide, of the way the skin looked wrong—slid in and out of his pupils like a bad film. At one point Airi cocked her head and watched him with small suspicion.
"Onii-chan," she said, around a mouthful of rice, "you're not acting like you. Are you sad? Did something bad happen?"
He almost told her. He almost let the rotting thing out of his mouth and into the kitchen light where it could be cleaned, explainable. Instead he blinked and made the smallest sound that pretended it was nothing. "I'm tired."
Airi's lower lip trembled. She reached out and took his hand as if to anchor him. "Promise you'll tell me if you're scared. I'll fix it. I'll be brave like a hero."
He wanted to tell her that she didn't have to be brave, that she should not carry his shadows on those small shoulders. He wanted to tell her that sometimes the world put ugly things in front of you and then slid them away again like tests you weren't allowed to answer.
He swallowed the words. "I promise."
She smiled then, sharp and bright. She hugged him so hard his ribs complained. For a second the world realigned. The image slid away.
Later, when he washed his face, the bathroom mirror looked like another life. He could see the tired set around his eyes. The skin under his jaw felt thin. He pressed cold water to his face until the house spun right.
He thought about calling Nozomi. He thought about knocking on Sota's brother's door and asking if he'd seen him. He thought about staying out on the street all night until the sun found him and told him what was true.
Instead, he went to his desk and opened the small black notebook he kept for class notes and collected half-formed thoughts. He scribbled a line in shaky ink.
> 15:04 — saw Sota behind west wing. Decomposition? Smell. No sign now. Question: hallucination?
He underlined the last word twice.
He couldn't sleep.
Hours crawled. The ceiling fan traced a slow, boring circle above his bed. Airi's breathing dimmed from the other room; the house settled into the usual small noises. The faint television from a neighbor's window hummed like a distant tide.
His mind refused the line of calm he tried to draw. Images bled: Sota's face with its wrongness, flashes of late-night variety shows where contestants screamed fake terror, a scene from some movie with a body covered with a sheet. He turned over the scenes like a stone, finding nothing inside.
He kept expecting a rational explanation to knock on the back of his skull—the part of him that loved measurements, the part that wanted to label experiences and file them away. "Optical illusion." "Practical joke." "You were tired." Any of them would do. He clung to the flattest one—he'd seen a shadow, plain and ugly—and tried to fold the whole night's weight into that small pocket.
Midnight passed. One. Two. At 2 a.m. he could no longer tell if the clock's tick was a sound or his own heartbeat.
He stood, quietly so as not to wake Airi, and walked to his window. The night was a hard thing, not the soft velvet scenes in anime. The alley was empty when he checked. The maintenance door sat like a watched mouth. The streetlamps threw their cones into predictable pools.
He pressed his forehead to the cool glass and let the world blur.
Something in him—some small, stubborn scientist—wanted test conditions. He told himself he would go back in the morning with coffee and a calm head and check the place with light and reliable angles. Verify. Repeat. Find that the evidence of horror had been a hallucination made by a tired brain.
Behind him, the house breathed. Airi's figure blurred in the doorway, a small silhouette that watched him with worry. She had not come to the window—that would be too dangerous for a little sister—and yet he felt her presence pressing like a palm on his back.
He turned and saw her watching from the other side of the room, eyes wide and brimming.
"Onii-chan." She said it too softly "You're really okay, right?"
He wanted to fold the night away and promise everything would be fine. He did not want to scare her, to leave her the echo of something he couldn't yet name.
"I'm fine," he said, the phrase thin.
Airi didn't look convinced. She padded over, climbed onto the arm of the couch where the blanket had unfolded, and curled a small hand in his. "Then tell me a story," she announced, as if that would be enough to push the dark away.
He tried to make the story light. He tried to spin it into something with monsters chasing silly treasures and brave brothers who always came home. His voice was a practiced instrument steady, low, familiar. Airi laughed in the places she'd learned to laugh.
For a while, the story worked. It patched the seam.
But the moment the tale ended and the house settled into the thin jazz that means sleep for adults, the image returned, bright and obscene in the hollow of his eyelids.
He thought of Sota laughing over coffee, the warmth in his voice, the idiotic grin. He thought of that laugh split by a grin that looked like the body he'd seen. He thought of Nozomi and her fingers tapping his sleeve and how close she'd been minutes before.
And he thought, with the cold clarity of something that had shifted under his feet, that the world no longer guaranteed even the small things he trusted.
He had the distinct and horrible feeling that something had been slid into place an impossibility that had not finished moving yet. Like a seam from an old shirt that pulled loose two threads and threatened to unravel the rest.
The house settled. Airi's breath evened. The clock ticked.
Kaien lay back down and stared at the ceiling until the ceiling pattern blurred into a soft, angry smear.
He told himself to sleep. He could sleep and in the morning logic would stitch this into sense.
Outside, in the alley he'd taken a hundred times, the maintenance door waited like a question.
He closed his eyes.
He could not stop the picture of Sota's face from coming back.
And then just as the house got the steady slow rhythm of the first moments of dawn there was a sound at his window.
A soft, deliberate tap.
It was not the frantic clamor of a thief.
Not the friendly knock of a neighbor.
It was a single, careful punctuation of noise.
Kaien froze.
Airi's breathing halted.
He could not say whether the sound came from reality or from the loose threads of his mind.
He moved to the window on legs that felt borrowed, fingers trembling as he reached for the curtain.
His throat made a sound he couldn't name.
And the night held its breath.