Ju Yi-dam's hideout was cluttered with various cables and components, but even within the chaos, there was a certain order. In this place where monitor lights never went out day or night, Jin Do-yoon and Ju Yi-dam were tracking the faint traces of the 'disappeared people.' Yi-dam reverse-engineered the mainnet's deletion logs and abnormal data flows, while Do-yoon dug deep into his memories of the vanished ones—their final moments, their trivial habits, and even their speech patterns—trying to piece together the puzzle.

"Damn, these bastards aren't amateurs either." Yi-dam muttered irritably, running his hands through his disheveled hair. His fingers danced across the keyboard, but all that appeared on the monitor were encrypted barriers and meaningless strings of numbers. "Moon Ga-hyeon, Oh Chan-woo... and you said there are more vanished ones that exist only in your memory, right? We need to find their common thread. Even the smallest detail."

Do-yoon closed his eyes and sank into the depths of his memory. The faces of the disappeared, their voices, the last conversations he'd had with them. Just before their existence was erased from the world, what common characteristic might they have shared?

"They were... deeply absorbed in something." Do-yoon slowly began to speak. "Chef Moon Ga-hyeon was trying to complete a new culinary philosophy, Detective Oh Chan-woo had almost reached the truth about some grand evil. And... another person, writer Baek Su-min. She was writing a novel called 'The Weight of Memory,' and its content was probing the vulnerabilities of the mainnet system. After she disappeared, all her works and records evaporated with her."

Yi-dam's eyes flashed with recognition. "Those who tried to escape mainnet control, or those who questioned the essence of the system? That's a plausible hypothesis. But that alone isn't enough to identify specific targets. The world is full of such 'dangerous elements.'"

Yi-dam began digging once more into the deepest part of the mainnet, into the code of the 'Existence Value Assessment Algorithm.' The faster his hands moved, the louder the cooling fans in the hideout became. Then it happened.

[WARNING! External intrusion detected! Reverse-tracking attempt!]

The monitor screen flashed red as blaring warning sounds erupted. Yi-dam's expression turned ice-cold. "Shit, damn it! Looks like the rats caught our scent!" He quickly severed all connections and deployed multiple layers of virtual firewalls. As if engaged in an intense cyber battle with an invisible enemy, his fingers never stopped moving. After several minutes of breathless silence, the warning sounds subsided.

"We almost had our hideout location exposed." Yi-dam said, wiping away cold sweat. "Their defense system is much more solid than I thought. Direct approach will be impossible for now."

Do-yoon felt powerless. It was like being lost before a massive wall. Then, like lightning, a possibility flashed through his mind. "Yi-dam, could there be... specific times or places where the erasures occur?"

"Time and place?" Yi-dam tilted his head. "Well, data deletion usually happens during late-night hours when traffic is lowest, but whether that can be pinpointed..."

"The vanished ones I remember—I mostly became aware they had disappeared in the morning. But the moment they actually 'vanished' would have been earlier. Perhaps... at the same time every day?"

Yi-dam turned back to his monitor. This time he began analyzing the mainnet's overall data traffic changes and the frequency of neural chip synchronization errors. After comparing graphs and figures for a while, his eyes widened.

"Found it...!" His voice trembled with excitement. "Every day at 3:33 AM. Precisely at this time, for a very brief moment, a data blackout phenomenon occurs repeatedly in specific regions. Like a sinkhole, all data flow temporarily evaporates. And right after this phenomenon occurs, reports of forced neural chip synchronization errors increase slightly."

3:33 AM. An ominous number, like the devil's hour.

"That blackout region... is likely the next erasure location." Do-yoon said in a low voice.

"Tonight at dawn, the area predicted to have the strongest blackout signal is... City Bay D-7 district, near the old industrial complex." Yi-dam said, displaying the coordinates. "Are you going? To witness that 'moment of erasure' directly?"

Do-yoon didn't hesitate. "We have to go. This might be our only clue."

3 AM. The City Bay D-7 district was deathly quiet. Only an eerie wind howled between the abandoned factory buildings. Do-yoon and Yi-dam hid on a rooftop of a derelict building, holding their breath as they surveyed their surroundings. Yi-dam checked real-time data flow on his portable device while Do-yoon sharpened all his senses.

Time passed to 3:32 AM. Their hearts pounded as if they might burst. A silence as if nothing would happen.

Then it happened. Warning sounds erupted from Yi-dam's device. "It's coming! D-7 district-wide data traffic plummeting! Blackout has started!"

Simultaneously, Do-yoon felt a strange pressure throughout his body. A stuffiness as if all the surrounding air was being sucked away in an instant. His neural chip crackled, causing subtle pain. And before his eyes, across the street in an old apartment building, he clearly witnessed one window flicker with an eerie blue light for just a moment.

"There...!"

The moment Do-yoon pointed with his finger, that blue light vanished. As if nothing had happened. But Do-yoon could tell. Just now, inside that window, someone had 'disappeared.' His unique neural structure was detecting the subtle 'echo' left by that being's erasure.

"We need to check."

Do-yoon moved as if to leap from the rooftop without hesitation. "Hey, Jin Do-yoon! It's dangerous!" Yi-dam's shout followed, but Do-yoon was already disappearing into the darkness. To not miss the final trace of that 'forgotten existence.'