I'm doing engineering in the instance.

He was awakened by the sensation in the soles of his feet.

It wasn't vibration, it wasn't sound, it was a kind of pressure—the pressure of concrete, dense, uniform, with a slightly rough, frictional feel, completely different from the touch of a chair in his personal space. Before he was fully conscious, his feet had already told him: this was the scene.

He opened his eyes.

Dam crest.

He stood on a maintenance passage about 1.2 meters wide. The concrete surface had fine anti-slip grooves, and water stains were embedded in the grooves—not rainwater, but seepage water that had seeped from inside the dam and climbed up along the micro-cracks on the surface, accumulating into a shallow layer in the grooves.

He didn't move immediately; he first scanned the area with his eyes.

Front: Downstream side of the dam, the dam face extends downwards in an arc, with a height difference of 82 meters. The toe of the dam disappears into the thin mist. The dam face is uneven in color, with several dark seepage marks, as if something pushed it outwards from the inside.

Behind: The reservoir. The water level was about 6 meters from the top of the dam, the water was grayish-green, calm, and without waves. He mentally noted the number—6 meters, 3 meters from the warning line, the water level was rising 18 centimeters every 15 minutes, which meant he was about... He mentally calculated: 3 meters ÷ 18 centimeters / 15 minutes, about 250 minutes, a little over 4 hours.

This is the first number after entering the venue.

The sky was overcast, the light was even, and he had no sense of direction. There was a wind coming from the direction of the reservoir, carrying moisture, and the temperature was about sixteen or seventeen degrees Celsius, six or seven degrees lower than his personal space. He sensed the wind direction and memorized it—wind direction was a potentially useful variable, though he didn't know exactly what its use was.

My wrist jolted.

He looked down and saw a new line appear below number C-0047:

"Scene #004 - Dam - Already Entered - Rules Displaying"

Then there are five explicit rules, appearing one by one in a font one size smaller than the numbers, arranged neatly.

He took out the memo and copied it down line by line, then marked each line with either "Known" or "To be verified." Rule 1 (Water Level Rise): Known, corresponds to fragment ①, value 18 cm/15 minutes, consistent with the fragment preview direction. Rule 3 (Weight Capacity Limit): Known direction, value obscured, to be calculated on-site. Rule 4 (One-Way Path): Known but misleading; is it spatially one-way or a time window? To be verified.

He paused after Rule 4 and added a line: "Fragment ③ Misleading warning is valid. Upon entering the field, prioritize verifying the actual meaning of 'one-way' and do not treat it as a spatial one-way situation."

Then he closed the memo and started walking.

The maintenance access road on the top of the dam extends along the dam axis. He walked about 30 meters to the left, found a place with a wide view, stopped, and did a "structural perspective" scan.

The scan results unfolded in his mind like a stress distribution map superimposed on reality.

Overall condition of the dam: The dam is 30 years old, within the normal aging range, with high seepage pressure in the dam foundation and three main crack areas inside the dam body.

He marked the locations of the three cracked areas in his memo, then walked towards the cracked areas to prepare for a close-up assessment.

The first crack is located about 12 meters below the dam crest. It is horizontal, about 0.3 mm wide, and runs horizontally. The depth is estimated to be less than 10 cm. This is a typical temperature crack, caused by the thermal expansion and contraction of concrete due to temperature changes. Almost all gravity dams that are 30 years old have this crack, and it is not a structural problem.

The second location: about 35 meters below the dam crest, there is an oblique crack, about 0.5 millimeters wide, running along the direction of the principal stress of the dam body. This is a load crack caused by water pressure, which is also within the normal range. As long as it does not continue to expand, it will not affect the safety of the dam body.

The third place:

He stopped at the third stop.

Approximately 20 meters below the dam crest, a sloping crack appears, about 0.8 millimeters wide, with the following direction:

He went through the direction of the crack in his mind once, and then again.

wrong.

The direction and depth of this crack do not conform to the cracking pattern of a concrete gravity dam under normal load or temperature change. Temperature cracks are horizontal, load cracks are along the direction of principal stress, and the direction of this crack is somewhere in between, but the angle and depth are incorrect—estimated using "structural perspective," the depth is more than 40 centimeters, far exceeding the range of normal cracks.

He wrote in his memo: "Third crack, about 20 meters below the dam crest, abnormal direction, abnormal depth, suspected non-natural cause, high priority assessment point."

Then he started walking towards the crack.

---

To get from the top of the dam to the crack, you have to go down the maintenance ladder on the dam face. The ladder is made of steel, and the degree of corrosion is within acceptable limits. He tested its load-bearing capacity and then began to descend.

After descending about ten meters, he paused, peeked out, and glanced at the appearance of the crack—

Someone is already there.

A man, his back to him, squatted in front of the crack. He was around fifty years old, wearing work clothes, gray ones, the kind of gray that had been washed many times, not new. His back was hunched, the kind of hunchback that someone who spends years squatting and watching things at a site would have, his weight on his heels, his waist not straining, and he could maintain that position for a long time.

Xie Chengzhou didn't say anything, and continued to climb down until he reached the person next to him and squatted down as well.

The crack was right in front of them, about 0.8 millimeters wide, running diagonally from the concrete surface inwards, its depth impossible to estimate with the naked eye.

Neither of them spoke.

About twenty seconds later, the man took out a thin wire from his pocket. It wasn't a professional crack depth probe, just an ordinary wire. He bent it slightly and probed it into the crack.

Xie Chengzhou looked at the depth of the wire and did some mental calculations.

The man pulled out the wire, glanced at it, and said, "Forty-three centimeters."

Xie Chengzhou said, "I estimate it to be over forty."

The man didn't reply, put the wire back in his pocket, and continued to look at the crack.

Xie Chengzhou said, "The direction is wrong."

The person replied, "Hmm."

Xie Chengzhou: "It's not a temperature crack, it's not a load crack."

The person replied, "Yes."

Xie Chengzhou: "The depth is also incorrect. A shrinkage crack wouldn't be forty centimeters deep."

This time, the man didn't speak, but simply nodded slightly.

Xie Chengzhou took out the memo, roughly drew the direction and angle of the crack, and then handed the memo over.

The man took it, looked at it for a few seconds, then took out his pen and marked an angle next to the line Xie Chengzhou had drawn: "27 degrees".

Xie Chengzhou glanced at it: "I'd estimate 28."

The man returned the memo, saying, "Almost."

Then he stood up, took a step above the crack, squatted down, and gently ran his finger along the edge of the crack. Xie Chengzhou also stood up and watched.

The man's finger stopped at a certain point in the crack.

"Here," the man said.

Xie Chengzhou looked down—the crack had a slight bend in that section, the angle changed by about three or four degrees, and it was not noticeable unless you looked closely.

"Cut marks," Xie Chengzhou said.

The man looked up at him, the first time he had ever looked at him directly.

What do you do?

"Construction work, project manager," Xie Chengzhou said. "And you?"

"Water conservancy," the man said, then lowered his head to continue looking at the turning point. "This crack didn't open naturally."

Xie Chengzhou went over the sentence in his mind, and then said, "It was driven by people."

"right."

Both of them fell silent for a moment.

Xie Chengzhou added a line to the memo: "Third crack - confirmed not to be of natural origin - suspected to be man-made - further assessment of the cause and purpose is required before treatment; direct treatment is not permitted."

He drew two horizontal lines under "cannot be disposed of directly".

The man stood up, patted the concrete dust off his trousers, then took a few steps to the left of the crack, squatted down, and began to look at another place—the location of the dam's expansion joint, the joint between two dam sections, about 2 centimeters wide, filled with waterproofing material.

Xie Chengzhou followed.

The man ran his finger along the edge of the waterproofing material and said, "Waterstop."

"Hmm," Xie Chengzhou said, "What did you figure out?"

The man pulled his finger out, rubbed it on his trouser leg, and said, "The edges are hardened, the elasticity is insufficient, and there is local compression deformation—it's not aging, it's abnormal stress."

Xie Chengzhou squatted down and touched it as well.

That person is right. The hardening degree of the edge of the waterstop does not match the age of the dam. For a 30-year-old dam, the aging of the waterstop should be uniform, but there is a section here that is obviously harder than the surrounding area. This is caused by concentrated stress, not natural aging.

He recalled the oddly shaped rubber waterstop he had seen in the props trading area of ​​Yuan City.

He wrote a line in his memo: "Expansion joint waterstop - abnormal stress - similar in shape to abnormal parts in Yuanshi Props Trading Area - to be verified: whether there is a connection."

They stayed on that section of the dam for about five minutes.

There were no self-introductions, no mention of "which instance I'm from," and no background information. The two of them were simply looking at the same crack, arriving at the same conclusion about the same issue, and then continuing to look.

In those five minutes, Xie Chengzhou realized one thing—there was no need to explain when talking to this person.

It's not because the other party understands everything, but because they are looking at the same place, using the same set of logic, stopping at the same point, and moving forward from the same point.

This was the first time he had encountered this situation since entering the realm.

Wang Bo is good, but he's a construction engineer, not a designer, so some things need explanation. Xu Kai is fast, but he's efficient, not structurally sound; they're not looking at the same thing.

This person is looking at the structure.

Xie Chengzhou wrote a line in his memo: "Together."

Just those two words, no parentheses, no notes.

---

As they prepared to head back towards the top of the dam, Xie Chengzhou sensed something.

It wasn't a sound, it was a vibration.

The vibrations transmitted from the soles of his feet were very low, between 15 and 20 Hz. They weren't continuous, but intermittent—every three or four seconds apart, each lasting less than a second. He had conducted numerous foundation vibration tests on the construction site, and this frequency was not from earthquakes, machinery, or water impacting the dam surface.

He squatted down and placed his palm flat on the dam surface.

The vibration was very clear.

He looked up at the water level—the baseline he had just noted was 6 meters from the top of the dam, but now it was about 5.82 meters, an increase of about 18 centimeters.

A 15-minute cycle.

He glanced at Rule 1: the water level rises by about 18 centimeters every 15 minutes, and the threatening entity enters an active state after reaching the warning line (3 meters below the dam top).

The current height is 5.82 meters, and there are still 2.82 meters to go before reaching the warning line.

The threat entity has not yet been activated.

But the tremors were already there.

He lifted his palm from the dam surface and wrote a line in his memo: "Vibration frequency approximately 15-20Hz, intermittent, interval 3-4 seconds, synchronized with water level rise, inference: the threat entity is sensitive to water pressure changes and is currently in a 'pre-activated' state; its sensing range may already cover the current location."

Then he added a note after that line: "Do not create localized water pressure changes."

The man also squatted down and placed his palm on the dam surface.

Neither of them spoke for about ten seconds.

The man raised his palm and said, "From the water."

Xie Chengzhou: "Hmm."

The person said, "The sensing mechanism is water pressure."

Xie Chengzhou: "Yes, that's my judgment too."

The man stood up, glanced towards the top of the dam, and said, "Let's go up first."

Xie Chengzhou stood up as well.

They began to walk towards the ladder, their steps steady, without running or panicking—rapid movement would cause footsteps to vibrate, which would be transmitted to the dam, where there is water, causing changes in water pressure, which would be perceived.

This was something Xie Chengzhou had thought of when he took the first step, and he believed that the other person had thought of it as well.

They walked about ten meters when the man suddenly stopped and looked back at the location of the crack.

Xie Chengzhou also stopped.

The man didn't speak, just looked at it for two seconds, and then continued walking.

Xie Chengzhou memorized this detail: before leaving, the man took one last look at the crack, not out of concern, but to memorize its location.

As they climbed back to the top of the dam, a sound came from inside the dam.

It wasn't a vibration, it was a sound—coming from inside the dam, like water flowing in a pipe, but the frequency was wrong, too uniform, too rhythmic, once every two seconds, each time lasting about half a second, with a fixed pitch that didn't change with the flow rate.

It wasn't the sound of flowing water.

Xie Chengzhou paused on the ladder and listened for a few seconds.

The person stopped too.

The sound lasted for about ten seconds, then disappeared.

Then came a period of complete silence.

During that silence, Xie Chengzhou sensed something—the sound didn't gradually fade away; it vanished all at once, as if something had stopped moving or changed direction.

He wrote a line in his memo: "Seepage Entity - Initial Perception - Sound Characteristics: Even rhythm, approximately 2-second intervals, fixed tone - Disappearance Method: Sudden stop, not gradually fading - Inference: Not random movement, purposeful - Current Location: Inside the dam, specific location to be determined."

He then closed the memo and continued climbing.

After climbing back to the top of the dam, the man stood on the maintenance passage for a while, looked around, and then looked at Xie Chengzhou.

"What's your name?"

This was the first time they had spoken to each other since they met that the conversation wasn't about engineering.

"Xie Chengzhou."

The man nodded: "Li Qian."

Two words, no fluff.

Xie Chengzhou wrote those two words down in the "person" section of his memo, and then added three more words after them: "Trustworthy".

He paused, then added a line: "Judgment criteria: When examining the same crack, using the same set of logic, stop at the same point. No explanation is needed, only confirmation."

Then he closed the memo and glanced at the water level.

5.64 m.

Another 15 minutes passed, and the water level rose another 18 centimeters.

Distance from the warning line: 2.64 meters.

Inside the dam, the sound reappeared, this time a little closer.