After we had opened the impossible door, I found myself at the beginning of a long, dark stone corridor. The air was stagnant and cold, and the silence was absolute, heavier than any silence I had known in the upper cavern.

  I stepped forward, and 404 followed like my shadow. The lesson I had just learned was still burning in my mind: "You didn't ask."

  After only ten steps into this desolate silence, I couldn't bear it. I stopped abruptly and turned to face 404. My gaze was as serious and sharp as a blade.

  "404," I said in a calm, decisive tone. "Before we go any further. Answer me honestly. Are we safe now?"

  He looked at me with his grey eyes. There was no hesitation.

  "No."

  I felt the cold run through my veins, but I forced myself to continue the questioning.

  "How... how many dangers have you sensed here?" I asked, my voice trembling slightly despite myself.

  "I do not know the total number," 404 said.

  I yelled in a suppressed fury, "What do you mean?! Answer my question!"

  404 said coolly, as if reading a report, "When we were on the cliff, I sensed three distinct threats within this range. The rock entity that fell into the chasm. The machine that has been neutralized. And there is a third thing... different from them."

  This novel is published on a different platform. Support the original author by finding the official source.

  I felt the blood freeze in my veins. I looked around the dark corridor. "Where is it?! Is it in this area?"

  And then, 404 said the sentence that would haunt me forever: "Close. Always close. I constantly sense its presence within a ten-meter radius of us. But I cannot pinpoint its form or exact location. It is here, but it is not here."

  "Here..." I whispered, feeling my hair stand on end. I spun around, seeing nothing but smooth stone walls. Ten meters. That meant it was with us in this corridor right now, accompanying us like death itself.

  "L-let's keep walking," I said, my voice barely audible. "But tell me immediately if anything changes."

  Our journey through the long corridor became a psychological hell. Every step was heavy. Every shadow seemed to move. I could feel invisible eyes on my back.

  "Is it still here?" I asked after a minute that felt like an eternity.

  "Yes."

  "Has it gotten closer?"

  "The distance is constant."

  "Has anything changed?"

  "No."

  This was our new rhythm. Silent steps, followed by a panicked question, followed by a cold, concise answer.

  After what felt like forever, I saw a light at the end of the corridor. The passage finally opened into another massive cavern. The atmosphere changed instantly. The silence vanished, replaced by a low, constant hum, with the rhythmic clang of metal echoing from a distance. The smell was different too—the smell of rust and ozone, the smell of old machinery.

  The scene before me was a majestic and terrifying industrial landscape. A vast hall stretched endlessly into the darkness, filled with silent assembly lines and giant robotic arms hanging from the ceiling like dead metal spiders. On the sides were the incomplete skeletons of machines resembling the Sentinel, abandoned in the middle of their construction. And in the center of the hall, massive presses and hydraulic hammers were still moving slowly, rising and falling in an endless, unstoppable motion.

  I stood at the entrance to this new area, gazing at this industrial hell. The sound of the machinery was deafening after the long silence. I turned to 404, fear filling my own throat, so much so that I could only whisper the question trembling on my lips.

  "Is... is it here?"