“River water does not interfere with well water,” Xue Yao said slowly. “It means the two are unrelated and do not interfere with each other.”
“Hey.” Lu Dantao raised her hand to interrupt. “I’m not talking about the implied meaning, but the phenomenon it refers to.”
A phenomenon?
Xue Yao pondered for a moment. He had indeed read about it in travel notes.
But why should he follow along with her line of thought?
However—
Across from him, Lu Dantao was staring fixedly at him, exaggerating her mouth movements: ‘Hurry up and say it.’
He let out a sigh. “It is said that in a certain place, the people dig wells by the riverside. Even when heavy rain pours and the river rises, it still does not contaminate the well water in the slightest.”
“Exactly! That’s it.” Lu Dantao snapped her fingers.
“Our current situation is exactly the same as the principle of ‘river water not interfering with well water’!”
“Do you know the principle behind river water not interfering with well water?” Lu Dantao asked. Without waiting for Xue Yao to speak, she moved straight on to the next part. “Alright, I’ll explain it to you.”
Xue Yao: …
“The water in a well comes from underground rivers.”
“And the water in a river comes from surface rivers. Because the two types of water flow through different places, the substances they contain are different. So although they look and feel like the same water, they cannot mix with each other.”
“So, that is why river water does not interfere with well water, and well water does not interfere with river water.”
Lu Dantao finished in one breath, then looked toward Xue Yao, whose expression remained unchanged.
A handsome face paired with those dead fish eyes made it impossible to tell whether he understood or not.
She couldn’t help but sigh inwardly.
As expected.
In education, the hardest part has never been the knowledge itself.
It is how to present it in a way that is both clear and accessible, to instill complex knowledge into people’s minds so that they can truly understand and grasp the underlying principles.
And what she was facing right now was precisely the most troublesome stage in education—
the gap between the learner’s existing level of understanding and the knowledge they were supposed to absorb.
Xue Yao was, quite clearly, a scientific illiterate. Explaining physics to him was no different from teaching advanced mathematics to a kindergarten child.
But there was no helping it. Who told her that as a researcher, she carried a heart full of great compassion?
Come on!
Let this ancient friend properly experience the charm of modern science!
Little Taozi’s class is now in session!
Lu Dantao patted Xue Yao on the shoulder, then raised her hand and slowly gestured across the surface of the river.
“Look at this river. Don’t be fooled into thinking it’s just a river on the surface.”
Xue Yao’s gaze swept over the small hand she had placed on him, and he gently brushed it away.
Lu Dantao did not mind. She continued facing the river as she spoke, “Actually, there’s also a well in this river.”
“But!”
She suddenly turned around and raised a finger at Xue Yao. “It’s not a man-made well, but a natural outlet of an underground river.”
“As we just said, river water and well water contain different dissolved substances. Among them, well water has more dissolved materials, so its density is greater than that of river water, which makes it heavier.”
“So,” Lu Dantao gestured with one hand above and one below, “this river is actually divided into two layers. The upper layer is river water, and the lower layer is well water.”
“According to my deduction, what actually happened is this—”
She suddenly flicked her head, brushing away the strands of hair blown across her face, then raised another finger.
“The murderer killed the victim, threw the body into the underground current at the riverbed, and then the body followed the current to the outlet, entering the well-water layer within the river, where it stayed sunk the entire time.”
Xue Yao folded his arms across his chest and spoke slowly, “Even if there is a well-water layer in the river, as time passes, the corpse will still eventually float up.”
Lu Dantao snapped her fingers. “Exactly!”
“This classmate, you’ve hit the key point.”
Xue Yao: …
“If it were ordinary well water, then yes, that would be the case.” The more Lu Dantao spoke, the more excited she became.
Ordinary well water used for drawing from wells simply comes from underground rivers. This kind of water does differ in density from regular river water, but compared to the density of the human body, that difference is practically negligible.
However—
“But if the underground current passes through certain special areas, for example, salt mines, then it is no longer an ordinary well-water layer.”
When underground river water contains salt or metals, its density undergoes a significant change.
“I’m guessing that the well water in this river must have passed through areas containing salt deposits, so its density is lower than that of the human body.”
“So the corpse can remain submerged in the well-water layer the whole time. Only when the body decomposes and produces gas, causing it to bloat and increase in volume, will it slowly rise, moving up to the boundary between the well-water layer and the river-water layer, and finally float to the surface.”
“Who knows!”
Xue Yao’s eyelids twitched at her sudden dramatics.
“I do.” Lu Dantao pointed at herself, then suddenly jumped to the side, mimicking a scrubbing motion. “You brought me here, and I went into the river to bathe.”
“My movements disturbed the river water,” she said, using both hands in front of her to imitate stirring. “They disrupted the original layering of the two types of water in the river. The corpse, which had already produced gas from decomposition and thus decreased in density, naturally floated up.”
After finishing her explanation, she lifted her head expectantly, waiting for a reaction from this illiterate classmate. But she saw that he was not looking at her at all. Instead, he was staring intently at the river, his gaze growing darker.
A sudden chill ran down Lu Dantao’s back.
‘What… did he see?’
She quickened her steps and moved closer to him, then carefully turned her head to look back.
The instant the scene on the river entered her sight, Lu Dantao’s pupils shrank abruptly.
On the surface of the river, one corpse after another slowly rose, emerging in succession. Their manner of death was similar to the one Xue Yao had just retrieved, only the degree of bloating differed.
These seemed to have died more recently than the previous one.
Lu Dantao was completely stunned.
She thought that in this lifetime, she would probably never forget the scene before her.
Even when she grew old, squatting at the village entrance, she could rely on this story to become the leading figure of the village gossip group.
But…
“How… are there so many?” she murmured.
If all of this had really been done by the male lead, then how many people had he killed? How many corpses were lying at the bottom of this river?
Was he some kind of butcher?
Wasn’t this generation’s Long Aotian supposed to be famously different, with an especially, especially gentle temperament?
For a moment, the riverbank fell into dead silence. Only the sound of the wind passed by, stirring the reeds into a soft rustling.
After a few breaths, the young man turned his head slightly and lowered his gaze, his eyes quietly settling on the face of the girl who was staring fixedly at the river, taking in every flicker of her expression.
The wind lifted Lu Dantao’s hair, and she casually tucked the loose strands behind her ear.
Xue Yao’s gaze shifted slightly to behind her ear. That patch of skin, perhaps rarely exposed to sunlight, was fair and clean within that small inch, like white jade—
flawless.
Sensing his gaze, Lu Dantao turned back to meet his eyes. Seeing the depth in his expression, as if he were scrutinizing something, she assumed he still did not believe her deduction.
She pointed toward the river. “Look. You see it now, right?”
“The situation is exactly what I said. When I bathed, I disturbed the water. When you went into the river to retrieve the corpse, you disturbed it again. And your movements were too large, so they all floated up.”
She muttered softly, “The facts are right in front of you, and you still don’t believe it.”
No sense of scientific practice at all.
“I never said I didn’t believe you.” Xue Yao withdrew his gaze, his tone calm.
He had never doubted her. What Lu Dantao said was simple and easy to understand. Even without prior knowledge, he could follow the logic. Moreover, everything on the river’s surface had already proven her words true.
There was just one thing he very much wanted to know:
“Where did you learn all this?”
From studying, of course.
Lu Dantao imitated his usual arrogant manner, curling her lips into a faint sneer, her face full of pride. “Naturally, from books.”
“That same 《Fat Ling Chronicle》 again?”
“Of course not.”
“Then what is it?”
Lu Dantao pressed her lips together. Why did he keep pressing the question?
She was starting to get annoyed.
Was she supposed to say 《Middle School Physics》, 《High School Physics》, or 《Principles of Mechanics》?
Would he even understand them or recognize them, this illiterate?
In the end, Lu Dantao held herself back and gave a vague answer to brush him off. “I just flipped through it in my father’s study. Some book about water management. I don’t remember the exact title.”
Xue Yao nodded. “In that case, your father must have an extensive collection of books.”
Lu Dantao waved her hand perfunctorily. “It’s alright, it’s alright.”
The corners of Xue Yao’s lips twitched almost imperceptibly, and he did not press further.
His gaze grew heavy as it swept across the surface of the river.
With so many corpses, there were likely even more beneath the water. Such large-scale killing and corpse disposal could not be simple.
If, according to what Lu Dantao had just said, the murderer threw the bodies into an underground river, and that underground river flowed through a region with salt deposits…
Xue Yao looked around. Could it really be as she had guessed, that Pei Di had established an independent kingdom in these mountains?
No, it did not make sense.
Pei Di already held overwhelming power over the court. The emperor was foolish and incompetent, had personally caused the Crown Prince’s death, and then pinned the crime of killing his own son on his eldest sister.
With the Crown Prince gone, the Third Prince was now most favored. And the Third Prince’s mother had been sent into the imperial harem by Pei Di.
Once the Third Prince ascended the throne, Pei Di would become the Regent.
Why would he go out of his way to come to Shouzhou, hollow out the mountains, and engage in all these unnecessary schemes?
Moreover, Shouzhou lay on the border and had never been a place known for salt production. If he wanted salt, would it not be better for Pei Di to go to Jiangnan?
Yet all the dead were connected to the military.
Could it be… the doing of the former subordinates of the Xue family?
Xue Yao’s mind was shrouded in doubt, countless speculations surging without end.
Lu Dantao stared at the corpses continuously surfacing, her mind also racing—
Since there was an underground current at the riverbed, then what she had just done was merely to stir things up. It could even be said that the water might not have reached her at all.
In other words—
She suddenly turned her head to look at Xue Yao, the corners of her mouth beginning to twitch uncontrollably. “I… you…”
Hearing her voice, Xue Yao turned back. He saw her pupils trembling slightly, yet there was not the slightest trace of fear or sorrow. Instead, her clear eyes were filled with laughter.
In the next instant, he heard her speak with delight, “Which means I didn’t come into contact with corpse water at all!”
Her gaze slowly swept over Xue Yao’s hands. She pressed her lips together to hold back her laughter, then casually took two steps back as if it meant nothing.
A vein at Xue Yao’s temple twitched faintly.
Lu Dantao retreated three or four steps away, her tone unable to hide her gloating in the slightest. “Only you… actually touched the corpse with your own hands.”
Xue Yao: …
His expression darkened instantly, his gaze unconsciously dropping to his own hands.
If both he and this fool had been contaminated together, it would have been somewhat better. But now it was only him…
The more Xue Yao thought about it, the more uncomfortable he felt.
Lu Dantao’s smile could not be suppressed at all. Mimicking his earlier whisper to her, she said, “I’ll take you upstream… so you can have a proper bath? Hmm?”
She imitated it quite well. The difference was that there had been helplessness in Xue Yao’s words, while hers was full of teasing from start to finish.
Xue Yao let out a cold laugh, thoroughly angered by her.
This fool… she had better just wait.
He turned back to glance at the mass of corpses in the river, then lifted his eyes to check the sky. Without another word, he turned and followed the riverbank upstream.
Lu Dantao watched his high ponytail swaying irritably as he walked. The frustration she had suffered from him over the past few days instantly dissipated, and she felt thoroughly refreshed.
She hurried after him. “Hey, where are you going? Upstream?”
In the summer afternoon, within the dappled forest, the young man with the high ponytail said nothing, striding swiftly through the woods.
Behind him, the girl with the small cinnabar mole between her brows moved lightly, skipping along.
At times she looked at the trees, at times she picked flowers.
While Xue Yao observed the growth of shrubs along the riverbank to determine the direction of the upstream flow, the corner of his eye remained fixed on the lively Lu Dantao behind him.
He suddenly spoke, his tone unreadable. “You didn’t even touch the corpse. You could have just stayed there. Why follow me upstream?”
Lu Dantao twirled the flower she had just picked, examined it to make sure there were no little insects, then carefully tucked it behind her ear. Only then did she speak slowly, putting on a sincere expression. “I have to accompany you.”
Xue Yao did not even turn his head. Only a completely undisguised sneer came from ahead.
Behind him, she secretly stuck out her tongue.
Did he think she was some big fool?
Staying there alone to guard a river full of corpses? She was not some professional mourner.
Besides, she needed a proper wash too. Even if she had not actually touched the corpses, she still felt disgusted.
And who knew where Pei Di was right now? What if he suddenly appeared? That would be disastrous.
But the Xue Yao walking ahead suddenly stopped, then abruptly turned back, casting her a gaze that was deep and heavy.
It startled Lu Dantao so much she jumped.
What kind of madness was he having now?
Sunlight filtered through the gaps in the leaves, outlining her figure with a hazy halo. The wildflower by her ear trembled gently in the breeze, setting off her delicate features. Her apricot eyes were clear to the bottom. Though she wore ordinary night-travel attire, not a trace of that darkness seemed to cling to her.
Just like when he had awakened two days ago, seeing her standing in the sunlight, as if she had become one with it.
Xue Yao’s gaze lowered slightly, and the doubt that had lingered in his heart for so long grew ever clearer and heavier.
This woman was definitely not Lu Dantao.
‘Who… exactly is she?’