Creeeeak... clunk. Ju Yi-dam's universal decryption tool finally did its job, and the heavy iron door, which looked like it had been rusted shut for decades, opened with great effort. The air that rushed out from within was cold and dry to the point of being barren, feeling like a vacuum where all life had ceased. Do-yoon found himself holding his breath without realizing it.

"Wow... now this is a proper haunted house," Ju Yi-dam whistled low as he cut through the darkness with his flashlight beam. Wherever the light touched, endless corridors covered in white dust stretched out before them. With each step they took, the sound of stepping on abandoned machine parts echoed hollowly.

From the moment he entered this place, Do-yoon felt a strange, oppressive sensation weighing down on his entire body. Countless 'echoes' of existence seemed to swirl together in chaos. Sadness, anger, despair, and even the faintest traces of longing. It was as if the very walls and floors of this place had been built from forgotten memories.

"A underground facility of this scale... it's not even in the MainNet official records," Ju Yi-dam muttered, checking his scanner. "The electromagnetic shielding is perfect too, and it's completely cut off from external networks. It's literally an isolated island."

How long had they walked? At the end of the narrow, dark corridor, a faint blue light was seeping through. The two approached the light carefully. And when they finally arrived at their destination, they were left speechless.

This was no simple underground bunker. It was a massive dome-shaped space. Endless rows of server racks stretched out, emitting blue light and vibrating with a low hum, with complex cable bundles and unidentifiable cooling systems tangled between them. It felt like entering the interior of some giant mechanical organism. On the ceiling, a sign reading 'Akasha Field Sector 1' glowed faintly.

"Is this... the 'graveyard of memories'?" Do-yoon muttered in a daze. "No, this isn't a graveyard. This is... a library. A massive archive preserving everything that's been forgotten." There was even a sense of awe in Ju Yi-dam's voice.

Then, Do-yoon began to hear unknown whispers in his ears. At first they were faint, but gradually more and more voices flowed into his mind. Laughter, crying, desperate voices calling for someone, and fragments of words whose meaning he couldn't understand. It was as if countless memories were trying to speak to him.

"Are you okay?" Ju Yi-dam asked, studying Do-yoon's complexion. Do-yoon barely managed to nod, pressing his hand to his forehead. The 'echo' of this place was on a completely different level from anything he had experienced before. It was too intense, too confusing.

They carefully made their way deeper through the server racks. And finally, they discovered a small room that seemed clearly separated from the other areas. On the door was an old nameplate reading 'N.M.S. Personal Research Lab.' It was No Min-soo's room.

The room inside was surprisingly modest. An old desk and chair, and research notes and data logs covering the walls. No Min-soo had clearly been conducting secret research related to the 'Akasha Field' here. Do-yoon picked up a notebook lying on the desk. The cover read 'Reflections on the Weight of Existence and the Density of Memory.'

The contents of the notebook were shocking. The 'Akasha Field' wasn't simply a place that stored forgotten memories. The MainNet system was transferring memory data of humans deemed to have 'low existential value' here, then 'purifying' it through a special filtering process. The purified memory data was being used to enhance the stability and efficiency of the MainNet system, or recycled as basic data for 'new personality generation.'

'Dissolution' wasn't a natural phenomenon or a simple system error. It was part of a 'data harvesting' process meticulously planned and executed by MainNet. No Min-soo had discovered this unethical truth and tried to expose it, and as a result, he had been 'disposed of.'

"This is insane...!" Ju Yi-dam cursed under his breath. His face was contorted with rage.

Do-yoon opened the last page of the notebook. There, what appeared to be No Min-soo's final message was written.

'They treat memories as mere information, but memory is existence itself. Erased memories will surely return. Like echoes, like waves. Seeker of truth, find the Core Repository. All answers lie there. But be careful. That place is the realm of sleeping gods...'

The Core Repository. It was the moment they learned through No Min-soo's notes of the existence of the deepest part of the 'Akasha Field,' the core where all memory data was concentrated.

Suddenly! With a sharp metallic scraping sound - screeeech - all the lights in the research lab went out and emergency lights began flashing red. At the same time, a low warning alarm echoed throughout the entire dome.

[Warning. Warning. Unauthorized intruder detected. Sector Delta-7 containment procedure activated.]

"Damn it, did we trigger something!" Ju Yi-dam shouted urgently, checking the exit, but thick steel shutters had already descended, blocking their path.

And in the darkness, dozens of red sensor lights simultaneously turned toward them. What could be heard in the silence was the sound of footsteps - eerie and rhythmic, like mechanical joints moving.

They were not human.