They did not reach the surface immediately.
Once they had passed the chamber of plates and returned to the main corridor, the medallion began to pulse violently again. It was not the steady signal that had guided Lin Yuan to the ruin, nor the controlled resonance with which it had responded to the formation relay. It was an insistent, almost urgent beat, directed toward one side wall of the corridor that, at first glance, held nothing special beyond a row of worn reliefs.
Lin Yuan stopped short.
Mu Qingxue, beside him, noticed the change before the others.
"What is it?"
Han Yue turned in visible annoyance.
"Please tell me you don't want to explore more."
Lin Yuan already had one hand over his chest, where the medallion burned through his clothes.
"There is something here."
Gu Tian frowned.
"I thought the same thing about several women in my youth. It never brought anything good."
"It's amazing you survived that long," Mo Qian murmured.
Lin Yuan ignored them both. He approached the wall. The carved lines did not show people or structures the way other sections had. They were circles crossed by vertical columns and a sequence of symbols so badly eroded that they would have looked like meaningless noise to anyone without an inner guide.
The medallion was almost vibrating like a trapped heart.
Mu Qingxue stepped close as well. She did not touch the stone.
"This wasn't active before."
"How do you know?" Han Yue asked.
"Because otherwise we would have felt it."
Gu Tian came up beside them.
"Move."
He used the tip of his staff to scrape away the gathered dust from two nearly invisible grooves. Then he fell silent.
"Curious."
"What?" Lin Yuan asked.
"The structure of the relief doesn't belong entirely to the same layer as the rest of the ruin. It was added later—or activated by another key."
Mu Qingxue's gaze shifted toward the medallion beneath Lin Yuan's clothes.
"Then it isn't reacting to the ruin. The ruin is reacting to it."
The words left a different thread of tension hanging in the air.
Mo Qian, who rarely missed a chance to joke, said nothing this time. Han Yue crossed his arms, clearly uncomfortable with anything that could not be solved by hitting it. Gu Tian watched Lin Yuan with eyes that were getting harder and harder to read.
"Do it," said the old man at last. "But if it opens a door to hell, I go first to see whether the wine is better down there."
Lin Yuan drew out the medallion.
In the pale light of the lamps it still looked like a simple gray disc, dull, almost vulgar. Only someone who had seen it react in the forest, answer the spatial tear, and function within the ruin could still accept the lie of its appearance. He held it before the relief. The stone gave off a very low hum.
One of the grooves fit the disc's edge exactly.
Lin Yuan pressed it into place.
The wall answered with a pulse of silver light, not blue, not red, but something quieter and more ancient. The weathered symbols lit from inside the stone, revealing lines that had remained hidden beneath age and wear. It was not a defensive seal.
It was a recognition lock.
Mu Qingxue drew a breath.
"This is not from this region."
"That was already obvious," Gu Tian muttered.
The stone opened not sideways, but backward, folding in on itself in concentric sections. Behind it appeared a chamber much smaller than the others. Barely enough room for three people at a time, and yet the sense of ancient density inside it was greater than anywhere else in the ruin.
At the center stood a black stone lectern. Upon it rested a palm-sized plate of pale metal, like dim silver, engraved with extremely fine lines. Behind the lectern, on the inner wall, there was a mural.
Lin Yuan stepped across the threshold first.
The mural stole his breath.
Not because it was beautiful in an ordinary way, but because it showed something no inhabitant of Stone Dry Village could ever have imagined. Beneath a sky pierced by vertical auroras rose impossible mountains, too high, too clean, held aloft by roots of light. Among them floated platforms, suspended bridges, and structures that looked like sects or palaces resting on the void itself. Higher still, formation circles the size of lakes orbited around a central tower that vanished beyond the limits of the wall.
At the lower edge of the mural, badly worn, human figures knelt—not in humiliation, but in reception, as if something were descending from the heavens to them.
And in the lower right corner, almost erased by time, there was a symbol.
A stylized firmament crossed by four ascending lines.
The medallion burned so fiercely Lin Yuan almost dropped it.
Mu Qingxue entered behind him. When she saw the mural, her composure cracked for real for the first time.
"This..."
Gu Tian approached with slow steps, and his silence said more than any exclamation.
"Don't say it," he muttered after a moment. "Because if you say it aloud, I'll start believing it."
Han Yue peered in from the doorway.
"What is it? Treasure?"
"Worse," said Mo Qian. "Looks like history."
Lin Yuan stepped closer to the lectern. The pale plate trembled lightly when the medallion approached. It did not leap into the air. It did not unleash dramatic light. It simply vibrated with a calm familiarity, as if it had been waiting a very long time for the proper key to stand before it again.
"Don't touch it yet," Mu Qingxue warned.
Lin Yuan glanced at her.
"Why?"
"Because we don't know whether it's sealed by blood, qi, or lineage recognition."
The last word lingered.
Gu Tian moved as close as he dared.
"The girl isn't talking nonsense. If this chamber was added by another layer of the system, the plate may answer to criteria that don't belong to the base ruin."
Lin Yuan looked once more at the mural's symbol.
He could not mistake it.
Not after all he had heard from the system, not after the fragmentary visions, not after the medallion's reactions.
That sign was connected to his origin.
Perhaps not fully, but truly.
"Then I'll use blood," he said.
Mu Qingxue opened her mouth, perhaps to stop him. She never got the chance.
Lin Yuan had already cut his thumb with the broken edge of a nearby plate. Blood welled up. He pressed it against the pale metal.
For a fraction of a second, nothing happened.
Then the plate lit from its center.
Not with fire.
With memory.
A current of silver light ran up Lin Yuan's arm and burst inside his mind as images.
He was no longer seeing the chamber.
No longer the ruin.
He saw skies vastly higher than any lower world could hold. He saw a procession of figures in white and silver moving along an avenue suspended between platforms of light. He saw banners carrying the same symbol from the mural. He saw a child in the arms of a woman whose face he could not fully make out, wrapped in dark blue cloth with the medallion gleaming like a cold star.
A woman's voice, clear and controlled by urgency, spoke from very far away.
"If the gate falls, follow the sealed route."
Another voice, male, wounded and furious:
"Let them find the firmament before the darkness does."
Then blood.
Lightning.
A rip in space.
And the child disappearing into descending light.
Lin Yuan staggered back with a choked breath. The plate released the light and went inert again upon the lectern. The medallion still burned. Mu Qingxue caught him by the elbow before he lost his balance.
"What did you see?"
Lin Yuan took a breath before answering.
"I don't know."
It was truth and lie at once. He knew too much to call it nothing. Too little to call it certainty.
Gu Tian stared at the plate with a frown so deep it looked painful.
"It activated from your blood?"
"Yes."
Mu Qingxue slowly released his arm.
"Then it is not a coincidence."
Mo Qian, from the doorway, looked far less easygoing than usual.
"Is anyone going to explain why the secret chamber in an old ruin reacts to the founder's blood as if it had been waiting for that specific founder?"
Han Yue crossed his arms.
"I don't care. I only want to know whether it helps."
"It helps too much," Gu Tian murmured.
Lin Yuan forced his thoughts back into order. He could not afford to become lost in visions, symbols, and enormous questions while time was still running outside. He pointed at the plate.
"Can we take it?"
Mu Qingxue examined the lectern.
"No. The activation already happened and the linkage has been spent, but if we remove it without checking the base the chamber may collapse. Besides, if it belongs to another layer of inheritance, it may be safer here until it is understood."
Gu Tian nodded reluctantly.
"I agree. There are treasures one does not steal. One studies them, if one lives long enough."
Lin Yuan rested a hand on the lectern. The medallion cooled slightly.
"Then we leave it."
Han Yue gave a short laugh.
"At last, something sensible."
Mu Qingxue, however, did not look away from the mural.
"Not entirely. This is not just a hiding place. It is a witness. And if there is one like this here, there may be others."
Lin Yuan knew it. He could feel it in his bones.
But he knew something else too.
"Not today," he said.
She looked at him.
"Not today," he repeated. "Today we leave alive and return to the mountain. Everything else comes later."
Silence accepted the decision before any of them did.
Even so, before leaving the chamber, Mu Qingxue stepped once more toward the mural. She looked at the symbol again, then at Lin Yuan, and said in a very low voice:
"Whatever your origin is, it did not begin in a small place."
Lin Yuan did not answer.
Not because he lacked words.
Because for the first time since Stone Dry Village, he had stopped truly believing he was only a boy abandoned by no one from nowhere.
He still did not know who he was.
But he could no longer pretend he belonged entirely to the world that had raised him.
They returned to the main corridor in more silence than before. Each carried something different now. Gu Tian carried questions. Mu Qingxue carried an uncomfortable certainty. Mo Qian carried curiosity too valuable for comfort. Han Yue carried impatience. And Lin Yuan carried a new weight inside his chest.
It was not fear.
Not exactly.
It was the sensation that while he was racing to save a poor mountain from a local clan, the past had just opened a much larger chasm beneath his feet.
And even so, he still had to keep moving.
Because the heavens could wait a little longer.
Heishan Rong would not.