The academy was quiet at night.
During the day, people moved between buildings.
Students went to classes.
To training.
To the cafeteria.
To the dormitories.
Footsteps echoed back and forth along the paths.
Doors kept opening and closing.
There was always someone passing through the corridors.
But night was different.
Many buildings were left with only basic lighting.
Corridor lights stayed at a fixed brightness.
The automated system recorded every door opening.
Recorded every person who passed through.
At night, the academy became clearer.
Because there was less sound.
Footsteps.
The opening and closing of doors.
The wind in the distance.
All of it was amplified.
Recently, some students had begun talking about the same thing.
It started with the lower grades.
They said they heard strange noises at night.
Not loud.
Like fingertips tapping against a wall.
One tap.
Pause.
Another tap.
The rhythm was slow.
Some students had stood in the corridor and listened.
The sound seemed to come from inside the wall.
One of them pressed his ear against it.
The sound stopped.
When he stepped away—
after a while—
it sounded again.
Some said they heard it three times in a row.
Some said only once.
Others said they heard nothing at all.
Another version came from the cafeteria.
Occasionally, people stayed there at night.
Some students did homework there.
One night, a student sat in the corner.
The hall was quiet.
Only a few rows of lights were on.
There were long gaps between tables.
He heard a sound.
Clink.
Very soft.
Like a spoon hitting a bowl.
After a while—
again.
Clink.
The rhythm was almost identical.
He looked up.
No one nearby.
The tables were empty.
The sound came again.
Clink.
He stood up and walked over.
The sound stopped.
There was only a bowl on the table.
A spoon lay beside it.
No one had touched it.
Some people saw shadows near the training area.
Late at night, the lights made the ground bright.
Glass walls reflected the entire space.
While passing by, someone saw an extra shadow inside.
As if someone was standing there.
But when they looked again—
it was gone.
At first, these were scattered stories.
Students told each other.
Some found them interesting.
Some treated them as jokes.
But gradually, a word began to appear.
Ghost.
It spread first among the lower grades.
They talked in the dorms.
Who heard the tapping.
Who heard the bowl in the cafeteria.
Who saw shadows at night.
The stories grew.
The explanations became more complex.
Some said that when passing certain places at night,
they felt someone behind them.
When they turned—
nothing.
Others said they saw an extra reflection in the glass.
But when they checked again—
it was gone.
These accounts spread.
From lower grades to upper grades.
Even the training area began to mention it.
Some students with sensory abilities reacted more strongly.
They said it wasn't an illusion.
It felt like something passed by.
Very light.
But real.
"Students with sensory abilities feel it most clearly."
Someone said that.
The word ghost began to be used more widely.
Eventually, it reached Seven.
That day, in the training area.
Several students were talking.
They mentioned the old school building.
The cafeteria.
The shadows.
Finally, the ghost.
Seven listened without expression.
He asked only one question.
"Time."
They looked at each other.
No one gave an exact answer.
Some said night.
Some said late night.
Some said after eleven.
Seven asked again.
"Location."
The answers were still inconsistent.
Cafeteria.
Training area.
Near the old building.
The only common point:
Always at the edge of vision.
Always disappearing just before confirmation.
Seven did not ask more.
—
That night.
The academy was quiet.
The road lights were steady.
Occasional wind could be heard in the distance.
Seven went to the cafeteria first.
It was one of the few places still lit at night.
There were vending machines.
Drinks.
Simple food.
They existed for students who missed meal times.
The taste wasn't important.
But people still came at night.
When Seven walked in,
a few students were there.
They sat at tables, studying.
Seeing him enter,
they stood up immediately.
"Seven."
He nodded once.
"No abnormalities?"
"No."
Seven looked around.
The cafeteria was quiet.
The vending machines glowed in the corner.
Only part of the hall lights were on.
Tables were far apart.
No one spoke.
Seven withdrew his gaze.
"Don't stay too late."
"Don't affect tomorrow."
After speaking,
he turned and left.
—
Seven went to the old school building.
On the surface, it was unmanaged.
But hidden cameras were placed around it.
Most students knew.
Seven ignored them.
He entered through the front door.
Inside, there was no surveillance.
Some upperclassmen came here secretly.
To gather.
Or to do things they didn't want recorded.
Of course, they had to avoid the cameras outside first.
Seven walked into the hall.
Several people stood in the center.
Sixth-year students.
They hadn't expected anyone to enter.
Seeing Seven,
they tensed immediately.
Two even covered their faces,
ready to leave.
Seven raised a hand.
"I'm not here for that."
They stopped.
Seven continued.
"I'm investigating the ghost."
The hall fell silent.
They exchanged glances.
No one moved.
After a moment—
A sound.
Thud.
Very light.
Like a fingertip tapping a wall.
Pause.
Another.
Thud.
The rhythm was fixed.
Not random.
Seven looked up at the wall.
Again.
Thud.
Pause.
Thud.
Seven said nothing.
He listened.
The rhythm repeated.
Short.
Long.
Short.
Pause.
After only a few cycles,
he confirmed it.
Not random.
A signal.
Morse code.
The pattern was simple.
It repeated only two words.
Experiment.
The sound stopped.
The hall returned to silence.
The others had heard it too.
They looked at each other.
Their expressions changed.
Seven didn't stay.
He turned and walked out.
—
The night wind was light.
The campus remained quiet.
Seven headed toward the laboratory building.
Lights extended from the corridor into the training area.
His footsteps were clear.
No one passed by.
The lab building was mostly closed at night.
Only basic lighting remained.
Seven entered the training area.
As he stepped in,
the lights turned on automatically.
The floor reflected light evenly.
He stopped at a specific spot.
Where 77 had been that night.
The air was stable.
Temperature normal.
No abnormal airflow.
Seven stood still.
After a few seconds—
he closed his eyes.
He entered the closed-eye state.
Perception radius fixed.
Three meters.
Vision disappeared.
Space simplified.
The ground appeared first.
A continuous plane.
Stable.
Unbroken.
Wall outlines formed at the edge.
Lines.
Planes.
Angles.
All existed as white structures.
Airflow became clear.
Subtle currents moved slowly.
No vibration in the ground.
No disturbance in the air.
In this state,
all living beings became shadows.
Moving shadows.
No details.
No shape distinction.
Only position.
Direction.
Velocity changes.
If someone entered the three-meter range,
he would only see a moving shadow.
Nothing more.
Now—
there were no shadows.
Only him.
Airflow stable.
Ground steady.
Walls unchanged.
Seven stood at the center.
He didn't search.
He compared.
Compared structural weight.
In this state,
space formed a stable model.
Ground.
Walls.
Air vibration.
All variables combined.
If something was missing—
a deviation appeared.
Seven waited.
Time passed.
Air remained even.
No shadows entered.
Then—
A slight difference appeared.
Extremely faint.
Almost unnoticeable.
Like a missing data point.
Not power.
Not threat.
Just a trace.
Something that had existed.
Incomplete now.
But remembered by the model.
Seven remained still.
Then—
A shadow appeared.
Behind him.
Half a step away.
No detail.
Just a vague outline.
It didn't move.
No velocity change.
No air disturbance.
No ground reaction.
It stayed for two seconds.
Then—
It shifted.
Not movement.
A directional change.
Part of it extended forward.
As if pointing.
The line extended beyond the three-meter boundary.
It held for one second.
Then began to dissolve.
Edges breaking apart.
Like data being deleted.
The structural weight vanished.
The shadow disappeared completely.
The space stabilized again.
Air normal.
Ground steady.
No new shadows entered.
Seven opened his eyes.
The training area lights were steady.
Glass reflected the entire space.
No one was there.
He didn't leave immediately.
He memorized the direction.
A corridor leading deeper into the lab building.
Seven walked.
Footsteps echoed.
Corridor lights steady.
No one passed.
He continued.
Through a passage.
Into the inner lab building.
The elevator was at the end.
Seven stopped in front of it.
Metal doors.
Buttons in two rows.
Upper floors normal.
Lower floors—few buttons.
One required permission.
Students usually couldn't access it.
Seven pressed the elevator.
The door opened.
He stepped inside.
The door closed.
Quiet.
Lights steady.
The panel on the wall.
Seven looked at one button.
The restricted floor.
The direction the shadow had pointed.
He didn't press it.
The elevator remained still.
Outside, the corridor stayed silent.
At night, the academy had very little sound.
Only the faint hum of the elevator remained.