Chapter 9 — The Thirteenth Landmark

The white light in the compartment is not a safety light. It indicates that the magnetic lock has released and the internal pressure has reached operating level. Khoi understood that before An. He pushed her through the side door, slamming the door behind him just as a stream of hot air shot out from the joint.

They ran in the narrow hallway. The gas measured on the device flashes yellow, then red. An coughed and choked, his eyes stinging. Khoi pulled the spare mask from the first aid bag and pressed it to her mouth.

“Breathe slowly!”

“Where is Nam?”

"Don't know."

A gurgling explosion echoed from the compartment. The floor vibrates slightly. Khoi turned around, but An pulled his hand.

“If the tank breaks, we don't have time.”

“Nam is still in there.”

“He knows the side roads.”

“He's opening for us.”

Khoi turned back. An cursed and ran after him. They found Nam at the end of the hallway, trapped behind a screen door. His hand was bleeding from being cut by the steel edge.

“This lock won't open,” Nam said through his mask.

An took the half-moon key. “Mechanical or electric lock?”

"Yes. Your father used to stutter."

She turned the key. It doesn't fit. Nam pointed to the slot next to it.

"Not that drive. Below."

An knelt down and found a small hole covered with mud. The key goes in, turn it twice. The screen door opened.

“Milestone 13 doesn't just record water,” Nam said. “It opens the way for maintenance.”

They escaped through a dry pipe leading to the back of the dam. When he reached the shore, An fell onto the grass, inhaling the cold air. Khoi checked Nam's face, then bandaged his hand with gauze.

“Do you know what's in the tub?”

Nam nodded. "Coagulant solution used for construction sites. Not enough to kill people immediately, but when exposed to alum water, it will create toxic residue."

“What is Tan Giang discharging it into the canal for?”

"Reduces treatment costs. At the same time, it makes the water cloudy, causing the optical measurement level to be wrong."

An turned. “RiverEye uses optical sensors?”

"Partly. Station number nine uses a pressure sensor, but the software takes data from the optical station to calibrate. When the water is cloudy, the system automatically lowers the number."

That's the missing piece of the puzzle. Milestone 13 is high because it is not connected to the software. Official data is low because chemical pipes cause the system to see a false water surface.

Bich called. An told briefly. Bich was silent for a few seconds, then said:

"I just received Tan Giang's environmental documents. The treatment lake is listed as a rainwater reservoir, without chemicals. If your photos prove otherwise, this is a criminal violation."

“Need samples.”

"The sample must be sealed according to standards. Do not bring it home yourself."

An looked at Khoi. “Do the rescue team have a sampling kit?”

“Yes, but not enough certification.”

“Enough to know what people are releasing.”

Nam suddenly stood up on his hands and knees. “I can get standard samples at the old testing station.”

“You are injured.”

“I still remember the process.”

They arrived at the city's testing laboratory around noon. The door is locked, but Nam has a spare card. Inside, the model refrigerator was largely empty. A technician quit his job leaving behind his notebook and sampling tubes.

An wears gloves and uses three sterile glass bottles. She took water samples upstream, samples at the mouth of the discharge pipe and samples at the North Shore. Each bottle is labeled with a code, time, coordinates, recipient and temperature.

Nam stands outside, does not touch anything.

“You used to do this procedure with my father?” An asked.

“Mr. Vu taught me not to take one sample at a time.”

"Why?"

"One pattern can only tell one moment. Three patterns can tell the direction of movement."

An wrote that sentence in the notebook. She didn't know how many teachings her father had left in others.

Preliminary results show colloid concentration Condensation at the exhaust nozzle is twelve times higher than the upstream model. The Bac Bo sample has begun to cloud, but has not yet exceeded the safety threshold.

“They are preparing,” Bich said when looking at photos of the results.

“Preparing for the flood?”

“For a flood with added chemicals.”

Bich wants to announce it immediately. An stopped.

“If published without a seal, they will say the photos are fake.”

“If they wait, they will release it all.”

“We need a third person to confirm.”

Nam said: "There is an independent laboratory in the neighboring province. But samples must go by road, not through the center."

Khoi holds the key to the rescue vehicle. “I'll take it away.”

Before they left, Nam's phone rang. He listened, his face turned pale.

“Who called?” An asked.

“Duy.”

Nam turned on the speakerphone. Hai Duy's voice was calm: "Mr. Nam, where are you?"

“I'm going to check the station.”

“You are not allowed to take samples arbitrarily.”

“This is the center's job.”

"The center has concluded. There is no unusual waste."

An walked closer to the phone. "Mr. Duy, I am Lam Minh An. I have an independent country."

“You are trespassing into a protected area.”

“I am protecting the people.”

“You don't understand chemistry.”

"I understand the data. Mark 13 records a higher water level than the system. Your chemicals cause the optical sensor to lower the number."

The line was silent.

“Her father also believed in a single number,” Duy said. “He died because he didn't know when to stop.”

“What do you know about my father?”

“More than you think.”

Duy hung up the phone.

Nam looked at An. “He never called me directly.”

“Because today I chose a side.”

They put the sample on the rescue vehicle. Bich comes along to film the handover sequence. The independent laboratory is more than an hour away from Ha Luu. When the vehicle crosses the bridge, the RiverEye system simultaneously updates level four warnings.

The outdoor speaker rang out: "North Bank residents immediately move to higher floors. This is a real warning."

An looked at the river. The water rose faster than usual. But there was no rain. Upstream does not discharge. Only the doors below the city are open.

At the lab, technicians check the seal code. The exhaust pipe mouth sample showed red results right in the first test step. He returned:

“Where did you get it?”

“Discharge line north of auxiliary dam.”

"This sample does not resemble rainwater. There are coagulant compounds and heavy metals."

Bich started to spin, but An raised his hand to stop.

“Didn't film his face yet.”

The technician looked at An, knowing he had just been protected.

When they left the room, a message from an unknown number appeared on An's phone:

This result does not save anyone. If you want to stop the flood, go back to the compartment and close the valve manually.

An looked at Khoi. “We have to go back.”

“No. The valve is locked from the center.”

Nam snatched the phone from her hand and read the message. “The sender knows the internal system.”

“And know the valve is open.”

Khoi started the car. “If we go back, there must be a way out.”

“We have three hours before the water hits dangerous levels,” An said.

Nam shook his head. “Two hours and seventeen minutes.”

“How do you know?”

He looked out the glass window, where the warning sign on the bridge turned red.

“Because I'm a model writer.”

The car turned back to Ha Luu. Behind them, the independent laboratory closed earlier than usual.

On the roof of the building, a strange camera followed the car until it disappeared from the bridge.

The independent laboratory returned official results the next morning. Water samples at the exhaust mouth contained coagulants, heavy metals and an unauthorized corrosion inhibitor appear in residential catchments. Technicians clearly state the method, storage temperature and sample receipt time.

“If you sign, this will be the inspection report,” Bich said.

The technician looked at her. “I sign if the sealing chain is complete.”

An gave a notebook to record each step: who took it, who received it, who preserved it, who opened it. She added the signatures of Khoi and Nam. Each signature brings them closer to the truth, but also makes the way back narrower.

“I don't want my name in the lawsuit,” Nam said.

“You can withdraw.”

“No. I just want to know how much I will be charged.”

Lawyer Thuan read the report and warned: "If published, Tan Giang will request the suspension of the lab, saying you took the samples illegally. But they cannot delete the results if they have an independent copy."

Bich sent reports to four editorial offices. An hour later, three places confirmed receipt, one place was silent.

An called Tuyet again. This time, she picked up the phone.

“Miss Lam, I only have five minutes.”

“You ever saw inhibitors in the old system?”

“I have seen test sheets being altered.”

“Who fixed it?”

"Son brought it. But Son is not the one who decides."

“Who decides?”

Snow sighed. "There was a woman who came to the lab. She didn't wear a name tag, just said she worked at the Department of Planning. She asked to change the time to take samples."

“Nguyen Dieu Trang?”

"I don't know the name. But she used the phrase: 'don't let the city pay for water'."

An asked more about the second version. Tuyet said she used to keep an original copy of the coupon in a drawer, but after the flood someone took it away. That person left behind a note saying “B-13”.

“Do you know my father received money?”

"I know he accepts. I also know he gives some back."

“Pay to whom?”

"For a family on the North Shore. They lost their children in the flood."

Be quiet. Ms. Hanh never talked about the money she was paid.

“Do you still have a copy?”

"In my storage room. But Son just arrived."

The call was disconnected. An and Khoi ran to Tuyet's house. The door was open, things were ransacked. A refrigerator falls over, sample bottles break on the floor.

Snow has no home. On the table is an envelope with An's name written on the outside. Inside there is a photo of a child standing by the canal and a handwritten receipt. The amount of money was exactly the same as the amount Mr. Vu received from Tan Giang, but the recipient was the child's mother.

Khoi looked at the photo. “This is my sister.”

An returned. “My father pays your family?”

"I do not know."

On the back of the photo is the line: “He couldn't save Thao, but he tried to save the rest of us.”

Khoi held the photo, his hands shaking. I don't cry. He just sat down on the doorstep, looking at the envelope.

An did not say any words of comfort. She understood that there were truths that did not make the wound any less; it only changes the perspective of the living.

Bich called to report to a newspaper that had published a report. Soon after, the website was hacked and the article disappeared. But copies have been shared.

“They are clearing the way,” Bich said.

An looked at Thao's photo and accepted the money. “No. They are cleaning up witnesses.”

Outside the door, an unmarked ambulance drove slowly past. The camera on the roof was facing them again.