Ever since Haruto appeared, Saten Ruiko and Misaka Misaka had already been staying here for a while.
Yet, there was still no movement from behind.
If not for the fact that both of them were still breathing heavily, no one could have told that they had just been through a chase.
So then, what exactly had been pursuing them?
"So, what was chasing you?"
Hearing Haruto's question, Saten Ruiko finally reacted.
She turned her head to look behind, only to find nothing there.
"T-This…"
For a moment, she didn't know how to describe it.
Haruto didn't press her, he simply waited in silence.
It was the little Misaka by the side who spoke up instead:
"Misaka didn't see anything, Misaka only heard strange noises, so Misaka got scared and ran away. Misaka Misaka explains seriously."
Haruto frowned.
Strange noises.
At this moment, Saten Ruiko also spoke up.
"This child suddenly ran out from that alley, and right after that, a terrifying sound came from inside. That sound… it was like some old monster speaking in a movie, but you couldn't make out the words at all. And then there was a series of clattering noises, like glass marbles dropping onto the ground. Because it was so scary, I grabbed this child and ran."
Thanks to Saten Ruiko's description, Haruto had a general grasp of the situation.
"So then, can you take me to that alley?"
Saten Ruiko hesitated a little.
The little Misaka raised her hand.
"Misaka can lead the way! Misaka Misaka does her best to promote herself, hoping to gain big brother Haruto's favor!"
At that, Haruto couldn't help but laugh helplessly.
All Misaka units shared their memories and experiences.
Perhaps because Haruto once rescued Misaka Unit 1, all Misakas displayed an abnormally high degree of affection toward him.
This was especially evident in Misaka Misaka, whose emotions were richer than the others.
Even though she was afraid, Saten Ruiko also decided to return to investigate the truth.
Her curiosity was nothing short of intense.
Since they hadn't cared about direction while running away, the three of them had to wander through the tangled alleys for quite some time.
Fortunately, Misaka Misaka's memory was exceptional—otherwise they might not have found their way back.
The destination turned out to be just an ordinary alley.
Aside from some clutter, there was nothing else. Even Haruto's sensing detected no other lifeforms here.
Saten Ruiko looked left and right in confusion.
"Misaka, do you remember exactly where you ran out from?"
Haruto asked quietly.
The little Misaka shook her head.
It was similar to how it had been in the original works—Misaka Misaka, as a "Command Tower," did not have fully developed physical functions.
She was not designed to act independently, only to serve as a controller.
Her act of escaping might have been no more than an instinct for self-preservation, leaving no memory behind.
At the end of the alley was nothing but a tall wall.
There was no other way forward.
Haruto walked deeper into the alley.
After only a few steps, he frowned.
Reaching a corner, he crouched down and touched the ground.
The cement pavement, which looked no different from its surroundings, suddenly flickered the moment he touched it—
Like a glitch in a video game.
As he pushed further, his fingers sank directly into the ground, as if phasing through a broken model.
Seeing this, Saten Ruiko's eyes widened.
"Wha-wha-what?! Don't tell me our world has bugged out?!"
Haruto withdrew his hand.
"It's just a holographic projection. There's something beneath here."
Then, Haruto pulled out his phone and dialed two numbers.
The first was to Aleister.
But it turned out Aleister didn't know about this underground space either.
This location wasn't marked on Academy City's structural blueprints. And Heaven Canceller's surveillance lines hadn't detected it.
Someone had carried out some kind of project here.
Most likely, this underground area had existed in the original terrain. When Academy City was relocated here, it was simply built over it.
Now, the underground cavern had ended up connected to Academy City.
The second call Haruto placed was to the Foundation.
Although he hadn't investigated further yet, he had a hunch—
That the two matters they had been chasing up till now, "Fantasy Hand" and "Deadlock," were likely connected to this underground area.
Otherwise, Heaven Canceller wouldn't have been so uncharacteristically silent.
And this underground place… was very likely far from normal.
Haruto immediately summoned a Mobile Task Force.
The nearest one was stationed in Tokyo, Japan—MTF "Wings of Freedom."
After the two calls, Haruto temporarily took the two girls away.
The Foundation would take over the rest.
MTF Wings of Freedom quickly arrived in Academy City, tasked with the investigation. Along with them came two squads of D-Class personnel.
After all, what exploration mission could be complete without D-Class?
At the target location, Wings of Liberty sealed off the surrounding area, and placed electromagnetic devices at the entrance.
The electromagnetic pulses disrupted the holographic projection, revealing a pitch-black hole.
At the same time, radar picked up the general structure underground. The entrance led to a sloping passageway, more than 300 meters long.
At the end of the slope was a vast hollow cavern, similar to a limestone cave.
This space lay beneath the Pacific Ocean.
Previously, Academy City's official cover story was that its island had formed from a volcanic eruption.
That explanation was only half true.
Originally, the region did have an undersea bulge created by volcanic activity. But it never broke the surface of the ocean, so it wasn't an island.
After Academy City was transplanted here, it became linked with this terrain. A squad of D-Class was sent in to explore the underground.
Exploration Report:
The D-Class descended the slope.
Along the way, the camera captured man-made traces.
The D-Class also reported:
"There's a discarded flashlight here. I think people must've been down there. Wait, what the hell is that? Urgh!"
In the lower part of the slope, one D-Class found several lumps of decayed flesh.
According to portable analyzers, the genetic structure was almost identical to humans—But from their appearance, it was impossible to tell what body parts they had once been.
The Foundation speculated these were artificial clones.
The D-Class continued down.
At the bottom lay a hollow chamber more than 50 meters tall.
It was enormous, and radar was interfered with, making full mapping impossible.
On camera, "houses" and "laboratories" appeared—clear signs of human construction. It seemed someone had modified this space into a research base, independent of Academy City.
The D-Class pressed further in.
They found large amounts of blood, bullet holes, and traces of combat—
But no human corpses.
Inside one "laboratory," made entirely of alloy, they discovered more. The alloy did not match any known Academy City material—it was a new type.
And it had extremely strong signal-blocking properties, impenetrable to normal communications.
Fortunately, the Foundation's comms used cross-dimensional technology, allowing the feed to continue.
The D-Class thoroughly explored the laboratory.
No people were found, but there were countless traces of human activity.
They retrieved research documents, most unfinished. Scanning revealed they belonged to secret projects once run by Academy City institutions.
After the Dark Side purge, these had been forced to shut down.
This lab too was stained with blood and battle marks.
Reconstruction suggested the facility had been attacked by some clawed creature. All personnel were either taken, or killed and their bodies removed.
The attack had been sudden—many experiments were still running when it happened.
After gathering intel, the D-Class prepared to leave for the next area. As they walked through a corridor, voices echoed from outside the lab.
It was human speech, in Japanese.
The word "Help," repeated again and again.