The strangest thing about death was the sound it made.
Not the screaming. Not the silence afterward.
But the hum.
A low, rattling frequency — like the purring of a cosmic engine. That was the first thing Itsuki Ren heard when he was declared clinically dead at the age of thirteen.
And yet, he woke up.
---
Three years later.
Itsuki stood on the roof of Minase Technical High, tie loose, headphones over his ears, eyes locked on something in the clouds.
"You ever stare at the sky too long," he muttered, "and feel like it's...watching you back?"
"Jesus Christ, not again."
The girl next to him rolled her eyes and snatched the earbud from his ear.
Her name was Yume Serika. Second-year. Track star. Paranormal freak. Currently banned from every shrine in Saitama for "accidentally" exorcising a wedding procession.
"You promised," she said, poking his forehead. "No more alien theories. No more death monologues. Just one normal week. One."
"I'm not talking about aliens."
She blinked. "Then what?"
Itsuki glanced at the sky again.
"They're called Resonants."
---
It started that morning.
The hallway clock froze at 8:44 a.m. exactly.
All the vending machines in the school dispensed the same drink: "UNKNOWN - TYPE V". No price, no label. Just a silver can with a spiraling black symbol.
Nobody noticed — except Itsuki.
Because he could hear it again.
That sound.
The same one he'd heard the day he died.
A trembling hum — coming from inside the walls.
Inside the people.
Inside himself.
---
By 12:06 p.m., four students were missing.
By 1:10, Yume's left eye began to bleed when she touched the silver can.
By 1:12, Itsuki opened it and drank.
---
The world cracked.
The hallway tiles peeled upward like paper.
Light bent. Sound bent. Time stuttered.
From behind the lockers emerged a creature not of flesh or spirit — but frequency. Its body was a skeleton of tuning forks, its eyes oscillating speakers, its fingers made of telephone cords and piano strings.
It screamed — a mechanical B-flat that shattered every window in a 50-meter radius.
Students fell to the ground, bleeding from ears, eyes, noses. And in the center of the chaos…
Itsuki stood completely still.
Not hurt. Not scared.
He was...humming.
---
"I thought you said no aliens," Yume whispered, crouched behind an overturned desk, blood trickling down her cheek.
"I said they weren't aliens," Itsuki corrected. "This one's different."
"What is it, then?!"
"A Resonant. A being made of hyper-accelerated emotion. They exist in ranges humans can't normally sense. Sound. Thought. Memory."
He touched his neck.
"They feed off unresolved trauma."
The creature screeched again — but Itsuki stepped forward.
And this time...he screamed back.
The hallway exploded in feedback.
---
When it ended, the creature was gone. Just a pile of melted metal and echoes. The corridor was a ruin of ash and glass.
Itsuki dropped to one knee, panting.
Yume rushed to him.
"What the hell was that?"
He looked up at her, pale and shivering.
"They're coming back," he said. "All of them."
"What do they want?"
He met her eyes.
"They want us to remember what we've forgotten."