The night before last.
Due to structural integrity limitations, the artificial island of Itogami had no true skyscrapers.
Instead, the city center was densely packed with mid- and high-rise buildings of roughly uniform height.
On the roof of one particularly plain and inconspicuous building among them, a girl lay prone.
She stared intently at the distant figure of Asagi Aiba entering the Keystone Gate.
"...He's making his move."
The girl's beast ears twitched slightly as she spoke to the smartphone lying on the ground before her.
"Good." The response from the other side of the phone came from a middle-aged man. "We begin as well. This is our best chance, on the island ruled by the Fourth Primogenitor."
"I know."
The girl took a deep breath and leaped from the rooftop.
The moment her feet touched the ground in the alley below, several beams of light pierced the darkness, illuminating the narrow passage.
"Huh?"
Before the beast-girl stood a group of police Neco-Arcs, their expressions uniformly benign.
The one at the front glanced briefly at the space beside the girl, then turned and led the squad away.
It wasn't illegal to enjoy the night view from a rooftop on Itogami Island.
"Weird..."
--+--
Keystone Gate, Sublevel 12. The Security Department of the Manmade Island Management Corporation.
This heavily fortified sector was the veritable heart and lifeline of Itogami Island. Asagi Aiba swiped the specially issued administrator-level ID card, passing effortlessly through all security checkpoints.
"They want me to go to the Zeroth Level?"
She'd just arrived, and now she was being sent somewhere else?
She looked at the phone in her hand, puzzled.
Inside the phone, Mogwai, as if aware of something, let out a strange synthetic noise that sounded almost like a smirk.
"Don't worry. It's not dangerous."
"Is that so..."
Asagi Aiba glanced at the phone, her hand in her pocket subtly pressing a button.
Tap... tap... tap...
The faint sound of her footsteps echoed as she ventured deeper into the bowels of Itogami Island.
Soon, the sound was swallowed entirely by the darkness.
--+--
Present.
Next to a high-end residential area near the city center, an empty space suddenly warped, and a group of girls materialized within it.
Minamiya Natsuki's gaze fell upon the hybrid Japanese-Western style house surrounded by concrete walls, her eyes darting towards the pitch-black windows.
This was Asagi Aiba's home.
"As expected, no one's here."
Even Asagi Aiba's parents were gone?
Her father was a member of the Itogami Island Council. He wouldn't just disappear without reason.
She glanced back at the thirteen small, golden heads following her and addressed Trimmau. "Find anything?"
"Nothing." Trimmau's eyes continued to flicker with a faint light. "It seems the surveillance footage for this area has been deleted."
"Then—"
Beep-beep.
Before Natsuki could finish, her phone chimed with a notification.
The bright screen illuminated her face as she read the message, her eyes narrowing.
"I'm in the Keystone Gate, Zeroth Level." — The message was from Asagi Aiba.
Trimmau, standing beside her, similarly narrowed her eyes. The message appeared to have been sent to a wide range of recipients.
Natsuki tapped the screen lightly, a flicker of doubt in her eyes.
The lowest level? There's nothing there...
No. There's something further down.
"Have any suspicious individuals entered Itogami Island recently?"
She directed the question at Trimmau, who had resumed her data search.
"No anomalies detected."
Arcueid's very first command upon taking over Itogami Island had been to strengthen border surveillance.
Natsuki didn't believe any suspicious person could slip past the Neco-Arcs and enter the island.
Which means... it's someone already on the island.
Someone on the island...
A figure abruptly surfaced in Natsuki's mind.
No wonder he handed the island over to Arcueid so willingly. He was waiting for this.
After a moment of silence, Natsuki spoke softly to Trimmau. "Contact Arcueid. And stop tracking Asagi Aiba. Find someone else."
"Who?"
"The Honorary Director of the Manmade Island Management Corporation—Yaze Akishige."
A small parasol unfolded in the girl's hand, moonlight glinting off its silvery surface.
A short while later.
Trimmau's voice sounded by her ear.
"Search complete. Yaze Akishige has recently been in contact with MAR."
MAR—Magna Ataraxia Research. A world-leading magic industrial conglomerate, a massive enterprise whose products ranged from cold medicine to military fighter jets.
Them...?
Natsuki's deep blue eyes narrowed slightly as she took the phone Trimmau handed to her.
The Keystone Gate was the name of the massive composite structure at the center of Itogami Island.
Its twelve stories above ground made it the tallest building on the island.
Its inverted-pyramid silhouette was visible from almost anywhere on the island.
The facility housed public offices like the municipal government, along with numerous hotels and commercial establishments, truly functioning as the island's keystone.
On the other hand, this colossal structure played another, more critical role.
It was the central management facility for the artificial island, comprising forty submerged levels.
This building, less than two kilometers in diameter, also served as the crucial link connecting Itogami Island's four constituent modules.
The Keystone Gate absorbed and buffered the distortions and vibrations caused by ocean currents and waves between the modules.
Without this system, the four sectors of Itogami Island would likely collide instantly or break apart and drift across the ocean.
The name 'Keystone' was utterly fitting for this vital facility.
"Hey? Natsuki-chan?"
Arcueid held her phone, looking up at the structure before her.
A large screen behind her cast light on her figure.
"To be brief. Asagi Aiba is inside the 'Cain's Coffin.' The Coffin is a submarine at the seabed below Itogami Island. It's the key domain for activating the 'The Cleansing.'"
"The enemy is likely the Honorary Director of the Manmade Island Management Corporation, Yaze Akishige. He—"
Click. Minamiya Natsuki's voice abruptly vanished from the call.
Simultaneously, an immense wave of magical energy surged beneath Arcueid's feet.
"The Cleansing"—the ultimate secret curse invoked by the Sinful God Cain to rebel against and take revenge upon the gods.
It was a power capable of arbitrarily altering the very fabric of the world.
The enemy's goal was clear. He wanted to use "The Cleansing" to achieve something.
And the most immediate target was...
"Me."
It seems he's not too happy about us taking over Itogami Island.
Arcueid playfully closed her right eye, sensing the contract bond with Minamiya Natsuki within her.
The steady flow of magical energy made the corner of her mouth lift in a slight smile.
Seems she's fine.
Natsuki has the Neco-Arcs with her, so no need to worry for now. In that case...
Might as well have a little fun here first.
"I do hope it turns into a fight~"
Her blood-red eyes shifted to look behind her.
The large screen, perfectly normal moments before, suddenly began to flicker violently as if suffering from a distortion.
The image on the screen twisted and morphed as if possessing a life of its own.
A girl with long, raven-black hair manifested within it, and then—
She grinned, her mouth stretching wide.
--+--
T/N: I have a Patreon! While it may seem empty as of now, webnovel will get 2 Chapters Every Day, and advanced chapters will be uploaded on Patreon.
It may not seem worth it now, but maybe in the future. Who knows!
[email protected]/AspenTL
If you guys wanna check it out.