Back in the cave, Old Stone sat on the stone bed, silent for a long time.
Gu Xiuyuan didn't speak either, just organized the things he'd brought back from the market today – a few low-grade spirit stones, a worn-out book titled "One Hundred Basic Questions on Cultivation," and a small bag of dried provisions. Old Stone had prepared half a month's worth of dried food for him, saying mortals must eat, unlike cultivators who could abstain from grain. Gu Xiuyuan thanked him, thinking that while this old man was stingy, he was still thoughtful.
After a long while, Old Stone spoke.
"Master," he said, his voice a bit hoarse, "today's events, this old man wronged you."
Gu Xiuyuan looked up at him.
Old Stone continued: "This old man has lived centuries, always cowering, avoiding Golden Core stage cultivators. If not for Master being here today, this old man would have handed over the ore long ago, wouldn't have talked back to Hu Laosan."
He paused, smiled bitterly: "This old man doesn't know what came over him, seeing Hu Laosan bullying you, something felt blocked in his heart. Maybe... maybe it's because Master treated this old man as a friend, and this old man wanted to be a real friend for once."
Gu Xiuyuan looked at him, those cloudy old eyes held guilt, and also something indescribable – like pride, or release.
"You didn't wrong me," Gu Xiuyuan said. "You stood in front of me, that's enough."
Old Stone paused, then smiled, his smile making his eyes redden.
"Good, good," he said. "Master doesn't blame this old man, that's good."
Gu Xiuyuan didn't say more. He picked up that "One Hundred Basic Questions on Cultivation" book and opened to the first page.
The book was worn, pages yellowed, some with water stains. The handwriting was copied by hand, crooked, many typos. But the content was relatively complete, starting from the most basic realm divisions, covering technique classifications, artifact grades, pill knowledge, all covered.
"Where did this come from?" he asked.
Old Stone came over to look: "Oh, that. Brought by a trading caravan last time, this old man traded a few pieces of ore for it. The writer was supposedly a loose cultivator, recording everything he knew. This old man doesn't know many characters, couldn't understand much, just tossed it aside."
Gu Xiuyuan nodded, continuing to flip through.
The book was simply written, but sufficient for beginners. Illumination, Light Opening, Fusion, Heart Movement, Spirit Stillness, Nascent Soul, Soul Departure, Soul Division, Harmonization, Tribulation Crossing, Great Achievement – eleven realms, each with simple descriptions. Later sections covered Golden Core stage, Nascent Soul stage explanations, and introductions to common techniques and artifacts.
Turning to the last page, he saw a line of handwritten text, different from the main text's handwriting, clearly added later by someone.
"Everything above is nonsense. Most important in cultivation is staying alive. Stay alive, then you have a chance at ascension. – A certain year, a certain month, left by someone passing through."
Gu Xiuyuan stared at that line for a few seconds, stunned.
This tone... somewhat like the last line in the jade slip.
He asked Old Stone: "Where did this book come from?"
Old Stone thought: "Last caravan brought it from Fengyuan Star. That loose cultivator is supposedly long gone, this book was written while alive, copied many times and spread around. That last line was probably written by whoever bought the book, common enough."
Gu Xiuyuan nodded, didn't ask further.
But he remembered the flavor of that line – a calmness that comes from having weathered storms and seen through worldly affairs. That person must have traveled many places, seen many things, to write such words.
---
In the following days, the two began an unusual cohabitation.
Daytime, Old Stone went mining in the caves, Gu Xiuyuan stayed in the cave cultivating, while using chemistry to process the ore Old Stone brought back. Evenings, Old Stone returned, they ate together – Old Stone took grain avoidance pills, Gu Xiuyuan ate dried provisions – then one taught cultivation, one taught chemistry, both learning enthusiastically. Old Stone had specifically set aside a bag of dried food for Gu Xiuyuan, teaching him how to ration it, saying before grain avoidance, mortals only needed a little each day, wouldn't starve.
Old Stone discovered that since Gu Xiuyuan arrived, his quality of life had skyrocketed.
First, ore purification. Previously, he'd mine a pile of ore, pick out the best quality to sell directly, discard the rest, loss rate up to seventy percent. Now Gu Xiuyuan taught him "acid washing" and "recrystallization" methods; those previously discardable ores, after several processing steps, ended up purer than the best quality. Every time the caravan came, he could trade for two or three times the spirit stones as before.
Second, pills. Old Stone had accumulated some savings over centuries, occasionally buying low-grade auxiliary cultivation pills, but their effects were mediocre. When Gu Xiuyuan got the pills, he scanned them with elemental vision – just half a second, minimal consumption – then said: "These pills have too many impurities, active ingredients only thirty percent."
Old Stone didn't believe it, so Gu Xiuyuan ground the pill, dissolved it with some reagent, filtered, evaporated, finally extracted a few tiny crystals. Old Stone took those crystals and almost broke through a minor realm on the spot – the effect was three times the original.
"Master!" Old Stone was so excited his beard trembled. "This, this, what divine method is this?!"
Gu Xiuyuan rubbed his temples – scanning the pill with elemental vision earlier, though brief, combined with frequent use over several days, meant the Purple Flame Heart's energy hadn't fully recovered.
"This is called purification," he said. "You pill refiners focus only on formulas, neglecting impurity effects on efficacy. From a chemical perspective, much of what you call 'pill toxins' are just impurities accumulating in the body."
Old Stone was completely convinced.
He began to think that this mysterious young man might truly be a gift sent by heaven.
---
Gu Xiuyuan's cultivation progressed steadily.
With elemental vision's help, he could clearly see the flow paths of spiritual energy in his channels, so his cultivation speed far exceeded ordinary people. But he also discovered elemental vision's limitations – each use consumed Purple Flame Heart energy.
After several days of experimentation, he summarized the pattern:
At full energy, elemental vision could be used continuously for about 200 seconds, consuming 0.5% per second. After use, the Purple Flame Heart automatically recovered, at a rate of about 5% per hour. Meaning from empty to full took an entire day.
So each use, he had to carefully budget, only using at critical moments.
That night, he sat cross-legged on the stone bed, eyes closed in cultivation. The Purple Flame Heart slowly rotated in his core, releasing warm energy. He guided this energy through his channels, one cycle, two cycles, three cycles...
Suddenly, he felt a tremor in his core.
The feeling was wonderful, as if something was about to break through the soil. He internally observed his core, saw a faint halo appear around the Purple Flame Heart, slowly expanding until it covered the entire core.
At the same time, he felt the spiritual energy flow in his channels accelerate, nearly doubling in speed.
Was this... a breakthrough?
He opened his eyes, somewhat confused.
Old Stone was sitting nearby, seeing him open his eyes, asked: "Master, what's wrong?"
Gu Xiuyuan thought, then said: "I just felt a change in my core, spiritual energy flow accelerated. Is this... a breakthrough?"
Old Stone paused, then jumped up, grabbing his wrist, probing with spiritual sense.
A few seconds later, Old Stone released his grip, his expression extremely complicated.
"Master," he said, voice trembling slightly, "you've reached the late stage of Qi Introduction, just one step from Foundation Establishment."
Gu Xiuyuan was stunned.
"How long?" he asked. "Less than half a month."
Old Stone smiled bitterly: "This old man knows. This old man took a hundred years from Qi Introduction to Foundation Establishment. Master took half a month... Master, who are you really?"
Gu Xiuyuan was silent.
He didn't know who he really was either. A doctoral student betrayed by his supervisor, a mortal who stumbled into another world, a lucky one who inexplicably merged with the Purple Flame Heart – which of these identities was real?
"Maybe it's the Purple Flame Heart's effect," he said. "It transformed my constitution."
Old Stone nodded: "Possible. The Purple Flame Heart is the Chongxuan Sect's ultimate Foundation Establishment treasure, said to greatly enhance cultivation speed. But even so, half a month is too fast... Master, your aptitude must be one in ten thousand."
Gu Xiuyuan didn't speak.
He just looked at his own hands, at the calluses and scars from experiments on those hands.
On Earth, he was an "academic misconduct offender," a "scumbag," a rat everyone shouted at. Here, he was a "genius one in ten thousand."
Fate, how ironic.
---
A few more days passed, Old Stone returned from the mine, his face not looking good.
"What's wrong?" Gu Xiuyuan asked.
Old Stone put down his basket, sighed: "Movement deep in the mine. I heard star beast calls, and not just one."
"Star beasts?"
"Ganyan Star specialty." Old Stone sat on the stone stool, poured himself a bowl of water. "This planet is naturally barren, no spiritual veins, but underground there's an ore called 'star iron,' good material for artifact refining. Star beasts feed on this ore, thick-skinned, teeth can bite through rock. Ordinary star beasts are equivalent to Foundation Establishment stage, powerful ones can reach Golden Core or even Nascent Soul."
Gu Xiuyuan thoughtfully: "They eat ore, so might their bodies contain high-purity mineral crystals?"
Old Stone paused: "This... this old man never considered. Hunted a few before, but bodies were always snatched by others, no time to study."
Gu Xiuyuan was about to ask more when a long howl suddenly came from afar.
The sound was rough, like some large beast, carrying far across the empty crimson desert. The sound carried a primal wildness that made one's heart uneasy.
Then another. And another.
Old Stone's face changed drastically, rushing to the cave entrance to look. In the night, several green lights moved in the distance, multiplying, like a pack of wolves' eyes, or floating ghost fires.
"Not good!" Old Stone cursed under his breath. "Star beast pack! They've been attracted by the commotion in the mine!"
Gu Xiuyuan also came to the entrance, squinting into the distance. He hesitated – should he use elemental vision? Purple Flame Heart energy was at about eighty percent now, using it might consume a lot.
But without it, he wouldn't know the specifics.
He gritted his teeth and activated vision, just for two seconds.
Over ten star beasts, some large as oxen, some small as dogs. The largest was double the others' size, covered in dark golden scales, its body containing high-concentration metallic elements, probably the Golden Core stage leader Old Stone mentioned. Those green lights were their eyes, especially conspicuous in the darkness.
He deactivated vision, his vision darkening momentarily, Purple Flame Heart consuming 3%.
"At least fifteen, one Golden Core stage leader," he breathed.
Old Stone's face was ashen: "Finished, finished..."
Gu Xiuyuan rapidly scanned the cave, mind racing. The stone wall at the entrance could hold for a while, but not long. Run? Outside was endless desert, no cover, couldn't outrun star beasts. Fight? Old Stone Foundation Establishment, he just started Qi Introduction, fifteen opponents, plus a Golden Core leader...
"Do you have anything flammable?" he suddenly asked.
Old Stone paused: "What?"
"Oil, dry grass, strong alcohol... anything."
Old Stone thought, then rummaged from a corner and produced a pottery jar: "This is lamp oil this old man usually uses, half a jar left. No dry grass, but these ore powders work?"
Gu Xiuyuan took the jar, looked at the pile of ore powder – waste from previous days' purification, mainly iron oxide and silica, very fine.
His mind rapidly flashed through several reaction equations. But this wasn't Earth, air composition might differ, formula needed adjustment.
"Hope is here," he said.
Old Stone's eyes widened: "Master, you plan to fight star beasts with 'chemistry'?"
Gu Xiuyuan didn't answer, just started acting.
He poured oil into a stone bowl, then mixed in ore powder, stirring quickly into a viscous paste. While stirring, he observed consistency – too thin burns too fast, too thick won't ignite properly.
Next, he tore rags from the cave into strips, soaked them in this paste, making over a dozen simple "incendiary bombs." Each wrapped tightly, ensuring burn time would be sufficient.
Old Stone looked at that pile of blackened rags, utterly bewildered: "What are these things?"
"Explosives," Gu Xiuyuan said. "But may not work, unknown air composition here, formula may need adjustment."
Old Stone was dubious, but no time for questions. The distant green lights drew closer, heavy footsteps and rough breathing already audible. The ground trembled slightly.
"Coming!" Old Stone gripped his flying sword, a centuries-old artifact, blade already worn.
Gu Xiuyuan shoved several "incendiary bombs" into his hands: "When they approach the entrance, throw these first. Remember, light and count two seconds before throwing, let the fuse burn in."
Old Stone nodded, palms sweating.
Outside, the first star beast appeared in view——
A bear-like monster covered in gray scales, ox-sized. Its nose sniffed the ground, clearly tracking human scent. Bloody maw revealed white fangs, saliva dripping from the mouth's corners.
Then second, third... soon over a dozen star beasts surrounded the entrance.
That largest one – scales dark golden, body size double the others – was the leader. It raised its head, looking at the stone wall gaps, emitting a deep roar. The sound made ears numb.
Other star beasts immediately began battering the stone wall.
"Boom! Boom!"
Stones loosened, dust showered down. The entrance rocks swayed under the impacts.
Gu Xiuyuan took a deep breath.
He knew tonight would be sleepless.