There was a "Method of Yellow and Red" in Taoist theories, which was also called the "bedroom arts".
This "art" was roughly the equivalent of sexology of ancient times, which covered aspects such as the basic knowledge, the skills of sexual activities, treatment of dysfunctions, conception, etc. It also linked sex to cultivation by claiming that in the process of sexual intercourse, a beneficial energy was produced, which could prolong one's life and eventually lead to immortality.
The ancient people were awesome! They could cultivate in bed. How unbelievably enjoyable must that be.
However, as time passed by, the real technique of the "cultivation in couples" was lost. Instead, many obscene methods were invented, which the Taoist community would not tolerate.
Kou Qianzhi of the Northern Wei Dynasty used to say, "The Great Dao is meant to be refined and non-aggressive, it would never permit such acts!" And according to Ge Hong of Jin Dynasty, "The act of sex alone will not lead to immortality, nor can it expel misfortune and bring blessings."
When time came to Song Dynasty, the bedroom arts became even more perverted, inventing practices such as using aphrodisiac substances, drawing energy from others during sexual intercourse and mesmerizing women through sex, etc., which had been sought after by harems of large families and emperors, as well as those fond of obscene knowledge. Hence, such practices had been passed down throughout history without exhaustion.
Depicted in the tattered book that Du Hong had picked up was none other than the method of drawing energy from one's sex partners.
The book started with specific techniques, followed by the corresponding manual. By drawing energy from males to nourish themselves, eventually, the females would be rejuvenated and become prettier, whereas their partners of the opposite sex would have vague ache in their loins and legs and be in low spirits, as if they were "used up".
'Are your kidneys worn out? Do you want to give them a "reboot"...' No, no, this is not that kind of novel! 
As mentioned before, everyone had their own path to follow. Old Priest Mo's Neidan, Tan Chongdai's talismans, Wang Ruoxu's Feng Shui, Li Suchun's corpse-refining, as well as Gu Yu's essence-consuming and Xiaozhai's Thunder Technique were all paths they chose to walk.
Du Hong was no different.
In a time like this when opportunities and risks coexisted, nobody's success or failure would raise a brow. Gu Yu and Xiaozhai did not think much of their two encounters with the woman and little did they know how high this woman would climb up in the near future.
Before anyone realized, it was mid-December.
The duo left Shengtian in early November and had been travelling around for over a month by now.
Xiaozhai's parents were calling more often, urging her to return home for New Year. Gu Yu was missed as well. Among the callers were Uncle Fang, Fang Qing, Granny Zeng, and Zeng Yuewei—just to list a few. They inquired from time to time about his whereabouts and general well-being.
What else could the two say? Their reply was always "we're still travelling and having a good time" and "we'll be back soon".
After Mt Emei, they took their time resting in Le Zhou. As usual, Gu Yu recorded their journey in Emei in a notebook. Together with the one on Tianzhu, the notes were three centimeters thick.
In them, he recorded in detail the road maps and locations of the nodes of the two mountains, as well as the resources they explored in the surrounding areas of the nodes, such as the stone wall of Tianzhu and the trees of Emei.
That's right, they called those "resources".
The resource structure of modern human society consisted of coal, petroleum, natural gas, or even reserves of the talented manpower. However, with the current situation, they might not have to wait long before the concept of resources changed into rare plants, iron ore rich with essence, or spiritual mountain ranges…
It was a delicate period. When the old rules had not been broken and the new ones were yet to be established, the common consent was: first come, first served.
They carried on as planned. There were three more stops: Pinghu Mountain in Shimen, Wangwu Mountain in Ji Zhou, and Tianshan Sect of Patriarch Sa.
They would visit Pinghu and Wangwu first, leaving Tianshan, the most important one, as the last. They learned next to nothing in Qionglong Mountain and Luobi County. If Tianshan were to fail them as well, then Xiaozhai would have little hope in completing her Dragon-snatching Internal Technique of Five Thunders.
Of course, little did they know that during this period, an important meeting was being held in the remote capital city.
The blazing incandescent lamp came to life, the abrupt brightness shooting directly at Li Suchun's face. He jolted, lifting his head as he broke out from a trance.
Seated in a chair, he was surrounded by thick and solid high walls of an empty room. Directly in front of him was a one-way mirror, keeping him from seeing whoever was on the other side.
"Time's up. Now, have you made up your mind?"
A voice came out of the speaker; it sounded majestic and dignified.
"Yes, yes I have. I'll do what you asked."
Li Suchun's eyes were unfocused, as if he had suffered much psychological torture.
"Good! Bear in mind that with the crimes you have committed, we could execute you ten times and even more! However, the state is in need of people with special talents and you are granted the opportunity to redeem your crimes by serving the country. As long as you work with us, we'll make sure you are rewarded accordingly."
Twitching his lips, the teenager remained silent.
Behind the glass, a white-haired old man stood in the center of the control room—he was the one talking to Li Suchun. He was about to go on when his bodyguard approached and reminded him in a whisper, "Chief, the meeting is going to start."
"Em, I see."
The old man waved his hand, "Watch him closely. Keep an eye on his psychological state."
The specialists in the room replied immediately.
The old man left the control room and went upstairs in a lift. After passing through many corridors, he finally arrived at a conference room, where eight people were already seated. One was in the seat of honor, with three on the left and four on the right.
He sat down on the fourth chair on the left side. "Sorry for coming late, but the good news is, that kid gave in."
"Humph! If it were up to me, we'd break him the tough way already. The hell with your diplomatic carrots. Totally a waste of time!" The second on the right snorted.
"That kid would yield to soft approach and not the tough hands. What if he's determined to give up on his life?"
"Giving up on his life? You're giving him too much credit…"
"That's enough. We're here for the meeting, not squabbling!"
The host knocked on the table. When those two quieted down, he instructed someone, "Read it!"
The private secretary sitting at the back stood up at once, a document in hand. "First, it has been agreed that the Bureau of Investigation and Management of Abnormalities and Unusual Persons is to be established. The bureau will be under direct jurisdiction of the central government. One Chief, two Deputy Chiefs and seven departmental heads are to be assigned to the headquarters, with an unspecified number of basic level personnel and peripheral workers.
A total of thirty-six sub-bureaus are to be set up in local areas, centering around major cities of different regions, with the same personnel structure as mentioned above. Those selected for the bureau should fulfill the following requirements—being loyal to the country, having flexible mind, being highly adaptable and capable of accepting new things…
The name of the bureau should not be revealed to the outsiders. The bureau is nominally under the jurisdiction of municipal governments. At times of crisis, all local governments are to follow the decisions of the bureau!"
The eight people were somewhat disturbed by the announcement. They were all quite high up on the power pyramid of the country, almost directly below the five State Councilors.
Apparently, their superiors had attached much more importance to this matter than they had expected. If this bureau was successfully set up, the power granted to its officials would be limitless!
The secretary paused for a second and went on reading.
"Second, starting from today, all domestic official media should pay attention to the guidance of public opinion. The local governments should be in charge of the specific methods and relevant trainings.
Third, starting from today, pay close attention to Taoist and Buddhist associations and their various schools and sects. Make efforts to communicate and exchange ideas on a frequent basis, so as to better understand them.
Fourth, regarding Li Suchun, it has been permitted in principle that research and experiments are to be carried out in Base 308."
There were ten points in total and when he finished, the room was dead silent.
After a long while, the host said, "So, our turn now. Any suggestions or ideas?"
The second on the left spoke first, "Can we organize a Taoist symposium and start a consolidated investigation?"
"That's too high-profile; there might be a leak. We could start with more specified targets. Isn't there a Baiyun Temple in the capital?"
"I see. I'll get on with it!" The second on the left nodded.
"That priest Wang reads the situation well. I think we could count him in," the fourth on the right added.
"Agreed. Oh, by the way, have you analyzed the information he offered?" The host asked.
"We have. In theory it sounds plausible, but actually…"
The fourth on the right seemed to find the words ridiculous as he went on, "According to him, the Corpse-Refining Technique has six levels and the final one is missing. The first five are called white, iron, bronze, silver, and golden in turn. Bronze corpses are intelligent enough to understand our language and the golden ones are not much different from human beings, but are powerful enough to turn mountains into level ground."
"Ha! That sounds like immortals to me!"
The third on the left blurted out, but immediately realized the inappropriateness of the remark and shut up.
The host coughed and switched the subject. "How are things going on Iron Mountain?"
"Samples and data were already sent back and we've been studying them over here. So far, we found nothing out of the ordinary."
Frowning, the fourth on the left chose his words carefully, "But in my opinion, these changes must have been stimulated by something else. Something we could not detect."
"I agree with you, but the bosses ask for substantial evidence, so let's keep studying them…"
The host also had no choice but to follow orders. He went on asking, "Oh, another thing, I heard that two unknown persons were also at the scene. Where are we on that?"
"I have something here."
The second on the right flipped open a file. "Based on investigation of the local police, a man and a woman turned out very suspicious. They arrived in Luobi on the day before the event and checked into a hotel. The following day, they rented a car, which they returned in the evening when they checked out of the hotel abruptly. According to the information provided by the railway system, they left for Le Zhou by train that same night and have not been spotted since."
"Ok, we don't have anything solid on them yet, but follow that lead anyway."
The host contemplated for a moment and said, "These two people sounded very problematic to me."
"No problem. I'll make some arrangements."
It was a very long meeting. After everything was arranged accordingly, the host suddenly sighed. "Guys, we've been enjoying these peaceful times for too long. I don't care what grudges you hold against one another or what power strife there is, this matter concerns the fate of our country. If I find anyone put their personal motives before the greater good, jeopardizing our mission, I will not tolerate it!"
The last sentence came out with such an imposing manner that everyone else stood up, moved by the solemnity.
Following the decree of the meeting, the local governments moved into action. The foremost task was to put together that Bureau of Investigation and Management of Abnormalities and Unusual Persons, or BIMAUP for short.
It was a major project. Other forces in the governments immediately reacted to it, probing for information implicitly and explicitly, which was all to no avail.
Shu Zhou was the quickest one. All personnel involved in the operation that day was assigned to the bureau and thanks to the effort of his patron, that scapegoat official actually benefited from the incident, becoming the, well, Deputy Chief of BIMAUP in Sichuan Province.
Meanwhile, those higher up in the chain of command also sent people out to follow up on investigating into Gu Yu and Xiaozhai while looking up their families. Based on the information provided by the wounded soldiers, the authorities established various personality models, from which they drew a conclusion:
These two people had the characteristics of ancient chivalrous swordsman. They preferred an unfettered lifestyle and disliked restraints, especially the coercion from authorities.
As a result, guideline of the superiors was to make friendly contact and communicate with them like equals.
Those sent to make contact were also to be carefully chosen. They had to be extremely amiable, if nothing else.
It was at this time of great uncertainty that our super duper capricious pair rushed their way into Shimen territory.
 TL/N: quoted above is a famous line of Chinese TV advertisement. Kidney is associated with virility in traditional Chinese medicine and this product is basically a tonic for the "overworked" kidneys.