The Immortal of Plague begins by establishing the root of lung fire.

"Find me a complete set of treasures, the kind with all the heart and soul," Qing San said. "Preferably, they've already been infected with the disease and are fully tamed."

To obtain a complete set of organs with the root of the disease, one would need to kill at least a formally initiated cultivator and dissect the organs. He was only at the initial stage of cultivation, so this would be extremely difficult.

"This is difficult," Song You said frankly. "I can't guarantee I can get it."

"Just remember this." Qing San put his hands in his sleeves. "I'll find a way to preserve the internal organs. You can take this book as a deposit."

Qing San shoved the blackened book into Song You's hands. Song You glanced down at the cover; it was blank, covered in grease and dark stains. He looked down at Qing San's face and said, "Elder Zhongzao has many disciples. Wouldn't it be more convenient for you to ask them to handle this matter while you're with the elder?"

Qing San grinned and said, "Just remember this, and I'll give you a reward that will satisfy you after it's done."

He didn't respond, and Song You didn't press further. He flipped through the pages, glanced at the yellowed paper and blurred text, and asked, "Where did this book come from?"

"A fragment of a manuscript found in a pile of old things." Qing San kicked away a piece of rubble at his feet. "Gong Jiu, Gong Ba's half-dead younger brother, probably also has a fragment of a manuscript. He definitely doesn't know that I have this."

"Does the method described here work?" Song You asked.

Qing San shook his head: "I don't have the Dao root, so I can't cultivate immortality. I didn't look closely. But seeing what happened to Gong Jiu, with half his body rotting away, you'd better not try it lightly. At least wait until you help me find all my internal organs and get the reward before you try."

"There's one more thing. Don't tell anyone about the stove-breaking. Right now, only the three of us know about it."

After Qing San finished speaking, he turned around, humming a song as he walked with small, quick steps into the depths of the canyon.

Song You tucked the book into his robes and placed it close to his undergarments. Qing San, even without his lungs, could still live; his immense strength and abilities were beyond description. He wondered what form he was in while living.

He turned and walked out of the valley, but after a few steps, Brother Jiang Yang followed from the side and behind.

"Junior Brother Song," Jiang Yangge lowered his voice, "what does that Qing San Tongzi want with you?"

"His private matters," Song You said, throwing out four words.

Jiang Yangge wisely kept quiet and didn't ask any more questions. The matter of the boy involved the elders, and any outer disciple who got involved would die. The two remained silent as they returned to the bungalow area via the same route.

He pushed open the door, revealing a dimly lit room. Song You bolted the door, walked to the table, pulled out a wooden stool, and sat down. He took out the black leather book from his pocket and placed it flat on the table.

The book's pages are turned, revealing contents that directly address the fundamentals of cultivation. Illnesses are sown later in life; some people are born with inferior spiritual roots, which cannot be changed. Since this is the case, one can try cultivating multiple sources of illness. Humans have five internal organs, six viscera, four limbs, and flesh—all can serve as cradles for cultivating these sources.

The detailed explanation that followed actually referred to it as "耧灶" (lǒuzào), which means to repeatedly sow the seeds of disease and maintain the body from decay.

The book then explains the difficulties of replanting different lesions. For example, some lung lesions belong to the fire element, while some kidney lesions belong to the water element. These two elements clash, and forcibly replanting them can lead to physical collapse. The book mentions that several deduced replanting routes are provided at the end, which can, to some extent, avoid the deadly situation of the five elements' mutual restraint.

Song You read the text word by word, analyzing the theories in his mind. The line of thinking was actually quite old-fashioned. It was impossible that those old monsters in the temple hadn't considered having multiple lesions on their bodies.

He turned the page, preparing to look at the deduction routes. His fingers twirled the pages, leaving a large gap in the middle, with jagged tears along the binding.

Someone had torn it out. Song You ran his fingers back and forth along the edge of the paper. Suddenly, he noticed that the thickness of the paper was wrong. He pinched the corner of a page, dug his fingernail into the gap between the layers, and pulled hard.

The paper was torn in the middle, revealing a thin, yellow paper inside. If Song You hadn't had such keen senses, he wouldn't have noticed it.

Song You followed the same method, disassembling all the interlayered pages and piecing them together on the table.

The yellow paper was covered with tiny characters, recording the true methods of using a seed drill.

The first step is to remove the organ and completely isolate it from the lesions already implanted inside the body. Once the newly implanted lesions have settled on the removed organ, they are then reattached to the body, allowing the two types of lesions to come into contact.

This method is extremely cruel and causes great damage to the body, but at the end of the yellow paper, there is a secret technique called the "Removing the Stove and Leaving the Method".

When the lesion removal process fails, this secret technique can be used to forcibly remove the out-of-control lesion, minimizing the damage. It also has a certain probability of retaining the failed lesion and adding it to one's original Dao root.

The lung fire root in Song You's body currently exhibits the characteristics of burning and protection. If he can use this secret technique to enhance these characteristics, his strength will increase dramatically, and his survival pressure will be greatly reduced.

This secret technique is extremely valuable, and since the paper has not been touched, Qing San most likely did not discover the papers hidden inside.

Just as Song You was pondering, his gaze shifted downwards and he noticed a line of small characters in the far corner of the yellow paper, which would appear as spots if not looked at closely.

"By applying this method, the survival rate of the seed drill can be increased from one in a thousand to one in a hundred."

Song You stared at the words and clicked his tongue in amazement. A one percent survival rate was achieved by increasing it tenfold. Without this secret technique, the mortality rate would be 999.9 per thousand. Does the cultivation world even have such small-print disclaimers? Human nature is truly unpredictable.

Gong Jiu must have obtained the torn section of the manuscript, which only contained a few deduced routes and not the secret techniques hidden in the interlayer. Gong Jiu rashly attempted to use the stove-laying method and surprisingly did not die instantly, only suffering half-rotten body damage.

It seems that those deduction routes are indeed unique. Song You made a plan to find an opportunity to get the incomplete copy that Gong Jiu had in his hands.

He refolded the yellow paper and tucked it into the hidden compartment in the corner. There was no rush with the stove; he was only at the initial stage of building firewood, his foundation was too weak. But there was much to be done in improving survival rates and enhancing attributes.

The diseases that affect ordinary people here are unlikely to have any effect on the ailments of cultivators; otherwise, predecessors would have tried this method long ago. But the Indians in the real world who withstood his lung fire ailment are different.

The Indian man who resold goods died after being infected by two lesions. In the context of spiritual cultivation, he might have awakened his spiritual roots. The mutated bacteria on these Indians are mostly capable of resisting the lesions.

This matter needs to be considered carefully and thoroughly. For now, we should focus on completing the basic practice of decocting medicine.

The next morning, just as dawn broke.

Song You pushed open the door and walked along the path toward the pharmacy.

Stepping into the inner room of the pharmacy, the eerie green flame in the medicine furnace still flickered. Jia Chunfang sat cross-legged on the wooden couch, her withered chest rising and falling weakly.

Song You walked to a distance of ten feet from the wooden bed, clasped his hands together and pressed down: "Disciple has come to report for duty."

Jia Chunfang opened her eyelids a crack, her cloudy eyes darting around as they landed on Song You: "How's your reading of those books going?"

"Yes, Master, I've memorized it all," Song You replied.

Jia Chunfang made a hoarse sound in her throat: "You're quick enough. Once you've memorized this, you can brew the medicine. One book every seven days, so it's really possible for you to finish in a month. Go to that empty stove over there, you'll start brewing the medicine today."

Song You turned and walked towards an unused medicine furnace in the corner of the inner hall. The furnace was about half a person's height, cast in bronze, and its surface was covered with dark red patches.

Before arriving, Song You had already reviewed the process of making Qingfei San (a traditional Chinese medicine formula). He took out snake-head grass, dried wood bark, and half an ounce of yellow soil, weighed them precisely, placed the herbs on the stone platform next to the stove, and opened the stove lid.

A thick layer of black ash had accumulated in the furnace.

"Use your lung fire to light the furnace," Jia Chunfang's voice came from behind.

Song You mobilized the lung energy in his chest cavity, and a grayish-white outer flame ignited at his fingertips. He inserted his fingers into the furnace, and as the outer flame came into contact with the black ash, the fire spread, filling the entire furnace with grayish-white flames. Inside the furnace were some strange yellow coals, which gradually lit up and emitted heat after coming into contact with the lung fire.

Song You carefully controlled the heat, keeping it at a minimum. He grabbed half an ounce of yellow clay and threw it into the fire. The yellow clay cracked under the high temperature, turning into fine powder that floated in the firelight.

Next, the dry wood bark was put into the fire. The erosive properties of the outer flame were activated, and the impurities on the surface of the bark were burned into blue smoke, leaving only a few drops of dark yellow juice.

Finally, there was the snake-eating grass, a herb with mottled medicinal properties, making it the most difficult to process. Song You concentrated intently, sending out several fine threads from the outer flame to penetrate the roots of the snake-eating grass, carefully removing the mud and toxins bit by bit.

The first attempt required intense concentration, and the entire process was very taxing. Song You's lung energy rapidly depleted, the leak in his body ached faintly, and waves of weakness washed over him.

He gritted his teeth and maintained the stability of the fire. After the time it takes for an incense stick to burn, all the medicinal herbs in the furnace had turned into liquid. The yellow clay powder wrapped the dark yellow juice and the green herbal liquid, which rolled and blended in the firelight.