The first knock came at 02:13.
Three sharp raps.
Pause.
Three more.
FULCRUM's eyes snapped open in the dark.
For a moment, he lay perfectly still on his bunk, listening to the slow, steady breath in his own chest and the low hum of the air system.
No blue light around the door.
No siren tone.
Just the faint memory of concrete under his boots and a painted number on a wall.
He exhaled.
"Not real," he said softly into the dark.
No one answered.
He sat up, swung his legs over the side of the bed, and put his feet flat on the cold floor.
He waited.
Nothing else knocked.
The climbing wall was technically closed.
Technically.
The lights in the gym were dimmed to low. The treadmills sat idle, weight racks silent. Only the wall at the far end had life—chalk dust hung faintly in the air under the glow of a single strip light.
KESTREL dangled halfway up, one knee crooked over a hold, harness snug around her hips.
"You're not supposed to be in here after twenty-three hundred," FULCRUM said from the floor.
"You're not supposed to be in a haunted stairwell either," KESTREL replied without looking down. "Yet here we are."
He huffed.
"Fair," he said.
He walked closer, craning his neck to see her better.
From this angle, all he saw was rope, harness, and a pair of boots braced against the wall.
"Belay?" he asked.
"Auto-belay's on," she said, and then, after a pause: "But I wouldn't say no to a second set of eyes."
He stepped to the belay station anyway, hands resting lightly on the backup line.
"You slept?" she asked, shifting up to the next hold.
"A little," he said.
"Any knocking?" she asked.
"Once," he said. "Sounded like the door."
"Was it?" she asked.
"No," he said. "Panel was dark."
She grunted.
"Well, if it turns into three children singing in harmony, call DOCSTRING," she said.
"And if it turns into you?" he asked.
She paused for half a second.
"Then it's definitely not me," she said. "I don't knock. I just walk in and tell you your harness is crooked."
He glanced up at her.
"Is it?" he asked.
"Metaphorically?" she said. "Probably."
She shifted again, reaching for the top hold.
"You scared?" she asked.
"Of stairwells?" he said.
"Of stairwells that talk," she clarified.
He thought about it.
"Yes," he said.
She let that hang between them for a few seconds.
"Good," she said. "Means you're sane."
She slapped the top marker and let herself hang back, trusting the auto-belay to catch.
It did.
She walked her feet down the wall in a slow, controlled descent.
He kept one hand on the backup line anyway.
When she touched down, she unclipped, then bumped his shoulder lightly with hers.
"You know," she said, "you don't have to go into every deep, dark hole they point at just because you're good at it."
"I know," he said.
She studied his face for a moment.
"You going to keep doing it anyway?" she asked.
"Yes," he said.
She sighed, but there was no surprise in it.
"Then at least keep letting me tie the rope," she said.
"I'll do that," he said.
"Good," she said. "Because your knots are an atrocity."
That won a ghost of a smile.
"Occupational hazard," he said.
She snorted.
"Coffee?" she asked. "The kind that doesn't taste like FUSE made it as a dare?"
"Tempting," he said.
She waited.
"Yeah," he added after a beat. "Okay."
She slung the coil of rope over her shoulder.
As they left the gym together, the echo of their footsteps faded into the quiet.
No knocking followed.
The tech bay lights were too bright for this hour.
Monitors glowed with frozen frames—university stairwell door, interior landing, empty steps. No movement. No faces.
FUSE sat hunched at one terminal, red-rimmed eyes fixed on a timeline scrub bar. Empty coffee cup tilted precariously on top of a stack of drives.
PATCH stood behind him, one hand on the back of his chair, the other wrapped around a mug.
"You know," she said, "you don't get extra hazard pay for staring at static until your brain melts."
"I get peace of mind," FUSE said. "Maybe."
"Peace of mind is my department," she said. "You're encroaching on my scope."
He leaned back, letting his head bump her sternum lightly.
"File a grievance," he said.
She rolled her eyes and brushed his hair back from his forehead with her free hand.
"You slept?" she asked.
"Define sleep," he said.
"Your eyes closed, and you stopped arguing with your own code for more than ten minutes," she said.
"Then no," he said.
She sighed softly.
"If I write you a prescription for eight hours unconscious, will you fill it?" she asked.
"Depends," he said. "Is the doctor cute?"
"She's very tired," PATCH said.
He smiled a little, then sobered.
"You still worried about him?" he asked.
She didn't pretend to misunderstand.
"Yes," she said.
"He came back up," FUSE pointed out.
"This time," she said.
He reached up, found her free hand, and twined their fingers together.
"Hey," he said. "You're allowed to care without making it your job to fix him."
"That's literally my job," she said.
"You know what I mean," he said.
She did.
After a while, she said quietly, "He said the knocking was manageable."
"Good," FUSE said. "If it stops being manageable, I'll rig a stairwell-free route to the mess just for him."
"That's not possible," she said.
"Watch me rewrite blueprints," he said.
She laughed under her breath and kissed the top of his head.
"Come to bed," she said.
He hesitated, looking at the frozen frame of the door.
"If it's going to open on its own," she said, "you staring at the footage won't stop it."
He sighed.
"Fine," he said. "But only because you asked nicely."
"I did not ask nicely," she said. "I prescribed."
"Semantics," he murmured.
They left the monitors to glow in the empty room.
On-screen, the stairwell door stayed shut.
Higher up, in a hallway most people didn't walk unless they had a reason, PRIORESS headed for her office.
Her hand barely brushed the handle before the door opened from the inside.
FOXHAMMER stood there, one hand still on the knob, brows raised.
"Checking for faces in the window?" he asked.
"Checking for you," she said.
He stepped back to let her in.
"Stairwell footage?" she asked, nodding at the terminal.
"Yeah," he said. "Watched him go down. Watched him come back up. Twice."
"And?" she asked.
"He keeps choosing the rope," FOXHAMMER said. "That's... not nothing."
She moved closer, shoulder brushing his.
"You still hear it?" she asked.
He knew she didn't mean SCP-087's lure.
"Sometimes," he said. "Less, lately. More when I see someone else on those steps."
She nodded.
"Echoes," she said.
"Yeah," he said.
Her hand found his.
"Stay?" she asked.
He squeezed her fingers once.
"Yeah," he said. "I'm not going anywhere."
Down below, in his quiet room, FULCRUM stretched out on his bunk again.
He stared at the ceiling for a long time.
When the next knock came—soft, distant, not quite at his door—he closed his eyes and counted his breaths instead of the raps.
One.
Two.
Three.
The sound faded.
For the first time since the stairwell, he fell asleep before he finished the count.