Chapter 6 — The Thirteenth Landmark

Khoi doesn't need An to tell him a second time. He started the engine, pulled the boat back from Mark 13 and then turned upstream. The water flow under the canal has an unusual pulling force, not strong but continuous, like a hand opening and closing.

“Where is door number three?” An asked.

“Below the auxiliary dam. But the control panel is in the Operations Center.”

“If the light on Milestone 13 is on, it means the valve is open.”

“Or someone wants us to think so.”

Khoi was right, but the smell of chlorine in the water made An unable to take it lightly. She dipped the quick test strip into the sample bottle. Blue turns purple after just a few seconds.

“There is disinfectant,” she said. “Low concentration, but not natural canal water.”

“Tan Giang has a secondary treatment lake nearby.”

“The treatment pond is not allowed to be discharged directly.”

“In Ha Luu, many things that are not allowed still happen.”

Khoi steered the boat through the right gate. Ahead, a concrete culvert appears behind a row of trees. The valve door is closed, but a white light is on on the valve body. An used binoculars to look. A person wearing a reflective vest stood next to the mobile control panel, bending down to check the wiring.

“There are people,” she said.

Khoi turned off the phone. The two people drifted along the water to near the shore. An noticed the silver ring on the other person's hand when his back was turned.

“What is he doing?”

“Attach a signal dummy device.”

An took pictures. The man suddenly turned around and shined the light straight into the water. Khoi pulled An to lie down. The boat glided close to the reeds, escaping the light.

“We have to notify the center,” An whispered.

“The Center may be controlling this.”

"Then call me Bich."

An turns on the walkie-talkie. No signal. She took her phone, sent photos and location to Bich, then received a notification that the server could not connect.

Khoi returned to the wharf by another route. When they landed, Bich was waiting, holding two cups of coffee and looking sleepless.

“I just got the photo,” she said. “But the file being sent was renamed before it reached my computer.”

“Change how?”

"Into a chain of code. Someone intercepts the intermediary."

Bich opened the laptop and inserted the B-13 memory card. A data recovery program runs slowly. She explained that the audio files do not record continuously, but are triggered when the pressure exceeds each threshold. Each file is thirteen seconds long, with a timecode in the hidden data section.

“This time code is forwarded exactly six hours,” Bich said. “The file says 16:10 but the system shows 10:10.”

“Why rewind?”

“So when people look at the log, they think the warning came later than it actually did.”

An opens the diagram. "If mark 13 is recorded correctly, the water exceeded the threshold at 4:10 a.m. on the old flood day."

“And today it detected that door number three opened at 10:13 p.m.”

Khoi put his hands on the table. “It means they're trying the process again.”

Bich pulled another file. The male voice rang out, younger, but unmistakable:

"The simulation command must have a new code. Don't let the old number return to the server."

An closes the laptop. “Give it to me.”

“I'll back it up first.”

“I need the original.”

“You need to live long enough to testify.”

Bich said harshly. An does not argue. She looked at Khoi, who was constantly checking his phone.

“Do you know who is in charge of sewer number three?”

"Previously he was station chief Dinh. He passed away after the flood."

“Is there a death record?”

“Convicted of traffic accident.”

“A sewer regulator died in an accident on the day the city needed witnesses?”

Khoi smiled unhappily. “Ha Luu has many accidents, yes at the time."

Bich received the message. She finished reading and showed An: Your account was accessed from the central IP. Someone knows you're restoring the B-13.

Phuc called immediately afterwards. His voice trembled.

“Sister, the white car just arrived at the shop. They asked mom for the key. I said I don't know.”

“Where is mom?”

“Mom is behind the kitchen. But someone entered the warehouse.”

An stood up. Khoi grabbed a life jacket.

“Back to the dock?”

“Go back to the shop.”

They ran across the street. From afar, An saw the tea shop door wide open, the glass of the cupboard broken. Two men are rummaging through a drawer. Mrs. Hanh was held in a chair, Phuc stood in front of her mother, clutching a screwdriver in her hand.

Khoi rushed in first. He didn't hit anyone, just used his body to push someone out the door, then locked his arms with a zip tie. The remaining person fled in a white car.

“Mom!” An knelt down.

Ms. Hanh was not injured, but her hands were shaking. “They asked for the film.”

“Which film?”

“Your father hid it in an old tea maker. I thought I threw it away.”

Phuc pointed to the red mixing machine in the corner of the warehouse. The back cover has been removed.

An opened the camera body. A small box of film was in the wire compartment, still intact. She took it out, but a piece of paper stuck to the outside had been torn off.

Bich looked through the window. “The police are coming.”

“You called?” An asked.

“No. Someone else called.”

Two minutes later, a patrol car stopped in front of the shop. The person who stepped down was not the area police officer but Hoang Nam. He wore a black jacket and was accompanied by two central guards.

“I was told there was a break-in,” Nam said.

Safely in front of the tea maker. “You came so fast.”

“I'm close.”

“How close?”

Nam did not answer. He looked at the person being held by Khoi, then looked at the film box in An's hand.

“You give it to me. This is evidence related to the regulatory system.”

“There is no seizure warrant.”

“I'm asking for safety.”

“Did you just come to save my mother or did you come to get the files?”

Nam lowered his voice. “I tried to warn you.”

“What warning? That if I don't sign, the contract disappears? Or that the data was altered because of the city?”

Nam looked at Mrs. Hanh, then turned to An. “You don't understand the person behind Duy.”

“So tell me.”

“It's not the right time.”

"When? After the North Bank floods again?”

Nam stepped back. “Let's leave town tonight.”

“Are you saying that as a witness or an accomplice?”

Nam's face changed. He signaled the security guard to leave, then said softly enough for only An to hear:

“Don't play the film unless someone has saved a copy. It will show you what your father did to door number three.”

An holds the film box. “I knew it existed.”

“I know because I helped him hide it.”

Nam left the shop before An could ask more questions. Bich looked after her, her face cold.

“Do you still trust him?”

An shook his head. “But he's afraid of something we haven't seen yet.”

That night, they did not open the film. Bich took it to her closed room, Khoi took Mrs. Hanh and Phuc to a relative's house. An sat alone in the tea shop, watching the river water rise another four centimeters.

Milestone 13 was still running through her head: 2.47, 2.63, 22:13.

Near midnight, An's phone received a video sent from a hidden account. The frame shakes, filming an old control room. On the wall is a sewer diagram. A hand wearing a silver ring flipped the switch. Then, Duy's voice rang out:

“It just needs to rise enough for them to sign. There is no need for another person to die.”

The video ends with the screen showing a number: 13.

An forwarded it to Bich. Three seconds later, the hidden account sent more text:

She wants to know who her father saved, find the last person to sign the order tomorrow.

Tomorrow, the city will have another flood. It's no longer a rehearsal.

An does not sleep. She sat in Bich's editing room, listening back to seventeen audio files with closed headphones. Each file has different background sounds: the sound of a fan, the sound of a pump, the sound of an iron door, even the sound of a cake seller at the ferry terminal. Bich used noise filtering software to separate each layer of sound, while An created a time table.

“File number three says 4:10 a.m., but the sound of selling cakes only appears after 6 a.m.,” Bich said. “Someone put the sounds in the wrong order.”

“Not an audio professional.”

“But people who know data, don't know life.”

An enlarged chart. Files are rewinded not in the same direction. File number five is two hours late, file number eight is six hours late, file number eleven was deleted four minutes midway through. Someone doesn't want to cover the whole flood, just wants to cover the times when someone says their real name.

Bich opened file number eleven. Behind the noise, a man's voice said: "Don't let Trang see the second version."

“What is the second version?” An asked.

"Don't know. But the next sound was the sound of a drawer being pulled."

They listen again and again. In the sound of scissors, there was the sound of metal hitting glass. An recognized the sound of a laboratory sample box.

“Snow,” she said.

“Testing lab technician?”

“My father once mentioned her name in his diary.”

Bich checks old records. Tuyet currently works at a private laboratory thirty kilometers from Ha Luu, specializing in testing farming water.

An texted to ask, but less than a minute later the phone number was blocked.

“She doesn't want to talk,” Bich concluded.

“Or have someone say it for you.”

Nam sends location to a secondary server. He told them to come before dawn, during system maintenance. An and Bich went with Khoi, while Phuc stayed with Mrs. Hanh.

The server is located under an old cultural house, where there used to be a community computer room. Nam opens the door with a mechanical key. Inside smelled of hot dust and burned wires.

“I'm not allowed to show it to you,” he said.

“You have lost your rights.”

“I still have a conscience.”

Nam turned on the screen. B-13 audio files appeared in the log from six months ago, but were not sent by Milestone 13. There was a person who uploaded them by hand, the temporary account was called “LQ-VU”.

An took a step back. “My father has been dead for twelve years.”

“The account could be fake,” Nam said.

“Who created it?”

“The login address is in the provincial meeting room.”

Bich took screenshot. An additional window appears, stating the moderator's name: Nguyen Dieu Trang.

Nam intended to close the system, but An stopped him. “Download a copy.”

“If it loads, the machine will notify.”

“Let him tell you.”

Plug in the hard drive. While data was being copied, a red warning appeared on the screen: “Unauthorized access — lock door for 30 seconds.”

Khoi looked at the door. "Way out?"

Nam pointed to the ventilation door, but the door was too small. Bich pulled the cabinet aside, revealing an air conditioning pipe large enough for one person to slide through.

“I went in first,” she said.

“You are the youngest,” Khoi replied.

An looked at the progress bar at 18 percent. She didn't want to give up the hard drive, but the door lock in the hallway turned.

Nam removed the cable. "Enough."

They took turns going through the tube. An heard the door being broken right behind him. When she went to the backyard, she saw an unmarked ambulance parked next to the fence. The driver wears a silver ring.

Khoi pulled everyone into the shade of the tree. Bich held her breath, holding the hard drive under her shirt.

Nam looked at the car, yes said: “I know this person.”

“Dang Quoc Duy?”

“No. The person in charge of Tan Giang's security.”

"Name?"

"Paint."

An remembers his father once wrote: "Son delivered the envelope to the lab."

The ambulance left. Nam didn't look at him, just said:

"If Son is on the server, it means they didn't just delete the data. They're looking for who saved the copy."

An looked at the hard drive in Bich's hand. “From now on, copies are not in the hands of just one person.”

They divided the data into four parts, each person kept one. Bich arranged to send the encrypted version to lawyer Thuan, Khoi hid part of it in the rescue warehouse, Nam placed part of it on the hospital server, and An recorded the time code in a paper book.

Before leaving, Nam looked at the old cultural house. "I used to think I would just enter a number. I didn't understand that one number could evict the entire neighborhood."

“Now I understand,” An said.

“Understanding is not enough.”

“Then help us do the rest.”

Nam nodded. In that moment, he was no longer a member of the center, nor a witness. He's just an engineer standing in front of a system that has gotten out of hand.