The Signature in the Drainage Ditch

The smell of wet concrete rose up from the entrance of the floodgate annex. It was different from the dampness of the hospital's equipment floor. Here the smell was seawater mixed with rusted iron. When I gripped the handle, the cold went in not through my palm but straight into my wrist bones. The handcuffs rang out briefly.

Memory came after the smell. The South Gate floodgate. The wet floor. The white work light. The log stamped with Yun Seola's name. Water pushing in. But there had been no sound. The floodgate alarm should have torn at my ears. In the scene inside my memory, there was no alarm sound. I didn't explain that blank space right away. The moment you explain a blank, it becomes a twist device. Right now it was an observed value.

"Did you stop because of the smell." Im Doyun asked.

"A memory cue."

"Memory grade."

"Trauma fragment. The floodgate opening and Yun Seola's name are strong. The absence of the alarm sound is recorded as a gap."

Seo Jin lowered her recorder. "You said gap. Not absence."

"Right."

She didn't miss that difference. Not because she was family, but because she was the one keeping the record.

Im Doyun didn't take my statement straight to fact. He made a small table. Present sensation, memory sensation, needs verification. Into the present column went the smell of wet concrete, the cold of the handle, the smell of seawater. Into the memory column went the South Gate floodgate, the work light, Yun Seola's name, the water. Into the needs verification column went the absence of the alarm sound.

"Why do you need this table." the technician asked.

Im Doyun answered. "So we don't mix memory statements with on site observation."

Looking at that table, I felt something like displeasure. Once my memory went into a box, it looked less real. But looking less real was exactly what was needed right now. Being certain doesn't make something evidence. Certainty moves people. Evidence stops them.

The inside of the annex was narrow. On one wall stood a floodgate test terminal, and on the other, a drainage diagram was mounted under a sheet of acrylic. If O Gyeongtae had come along, he'd have sworn the moment he saw that diagram. He was still back at the hospital, having his hands and his cough checked. Jang Yura stood in front of the diagram instead. She didn't know the full floodgate structure. She admitted what she didn't know right away.

On the floor were thin, dried water marks. They weren't traces of a recent large flood. There were three kinds of footprints. Work boots, sneakers, and slip resistant overshoes. The technician said the overshoes were something facility staff used often, but he didn't know whose they were. Im Doyun photographed the footprints without treating them as confirmed evidence.

"Until we cross check against the entry log, this is just a trace at the scene."

"Isn't it evidence?" Minchae asked.

"A trace that could become evidence."

That distinction should have felt familiar by now, but it still moved slowly. Jang Yura called out the valve number from the floodgate diagram over her radio. It was a way of asking O Gyeongtae, who wasn't on site, to confirm. A moment later his voice came back from the hospital. There was a cough mixed into it.

"That number matches the South Gate auxiliary line. But in test mode, water isn't supposed to come over. That's normal."

"Possibility of abnormal."

"Possible if the manual valve was left open. Or the log is wrong."

Yura put a finger on the diagram. "We check both."

O Gyeongtae hadn't shown up in person, but his role remained. His hands and his cough kept him off site, and the radio only sent back what he knew. Nobody can be everywhere. This time, that limit made the story feel less like a lie.

"If someone falls in here, where do they go."

The technician pointed a finger in the drainage direction. "The South Gate main drainage channel. Right now it's in test mode, so there's no actual opening."

"Can test mode kill someone."

"If the commands get tangled, water comes in."

"Then the test is a scene too."

Im Doyun turned on the audit terminal. On the screen appeared an authorization code from the same family as the hospital's red door. `YS-SOUTH-GATE-AUTH`. This time it was a floodgate test log. There was a blank between the execution time and the approval time. There was no record of a command being pressed, only a trace of approval.

Seo Jin didn't demand filming the moment she saw the screen. "Don't scroll. Start from what's showing right now."

The technician stopped his hand. At the bottom of the screen was a field called `executor_id`, and its value was blank. Below that, `proxy_token` was grayed out. It wasn't even clear whether it could be clicked. The approval time was fourteen seconds later than the command time. In a normal system, that order was strange. But being strange alone doesn't make it tampering.

Im Doyun took three shots. Full screen, the blank field, the timestamp line. Seo Jin didn't take the same shots with her own camera. Fighting over who got to shoot the original would cost time. Instead she took down the time and file name of Im Doyun's shots.

"When do I get my copy."

"A review copy, after the original is sealed."

"A review copy means nothing if it's deleted first."

"That's why I'm recording the file name now."

Seo Jin swallowed her complaint. She knew it too. Fighting now would cut into the time they had to look at the log. Yun Seola's name was on the screen, and the blank field looked smaller than that name but was more dangerous.

"Yun Seola's authorization." I said.

Seo Jin asked right away. "Direct manipulation?"

"Unconfirmed."

"Good. Now that's the first thing out of your mouth."

She wasn't satisfied. She'd judged that things had gotten a little less dangerous.

Im Doyun filmed the log with the sealing camera. "Same authorization family as the hospital log. Direct executor unconfirmed. Approval time and command time don't match."

"Why do blanks happen." Jang Yura asked.

The technician hesitated. "Proxy approval, after the fact synchronization, log corruption. All three are possible."

"Not possible, what can we distinguish right now."

"Nothing."

"Is there no fourth option." I asked.

The technician looked at me. "A fourth?"

"A case where the authorization holder pressed it directly, but only the executor field got wiped."

"That's possible. But even that case can't be distinguished without the original log."

Seo Jin wrote it down right away. "Direct manipulation possibility not excluded. Proxy possibility not excluded either."

That sentence neither saved Yun Seola nor condemned her. I didn't like that. Part of me already wanted to fix her as the traitor. Fixing it makes the next move easier. But easy moves usually collect their cost later.

I looked at Yun Seola's name. The suspicion held. But the shape of the suspicion had changed. The signature I'd seen at the hospital was here too. That wasn't a coincidence. At the same time, it didn't mean she'd pressed it with her own finger. I had to hold both sentences at once. Holding just one makes things easier. The easier side is usually the more dangerous one.

Im Doyun requested a live test of the floodgate alarm. The technician tried to hand out headsets, but Jang Yura refused.

"We need to hear the actual sound. Just confirm there are no patients and no residents nearby first."

"The alarm is loud."

"That's why we confirm."

The test button was pressed. The alarm went off immediately. The metal walls threw the sound back, and the handcuffs trembled on my wrist. My ears hurt. Seo Jin pulled her recorder a little away from her body. Jang Yura winced but didn't step back. This sound hadn't been in my future memory.

The technician pointed at the panel. "Alarm circuit normal. Test delay, 0.8 seconds."

"What are the conditions where the sound wouldn't go off?" Jang Yura asked.

"Speaker power cut, circuit bypassed, or a person whose hearing was already damaged."

I stopped on the third condition. At the South Gate in the future, I might already have been in shock. Maybe there really had been an alarm, and I simply hadn't heard it. The moment I used that possibility, my suspicion of Yun Seola weakened a little. I hated that it weakened, but I still had to use it.

"The silence in my memory isn't confirmation that there was no alarm." I said.

Seo Jin looked at me. "Say that again."

"In the future memory, I didn't hear the alarm. The cause could be the alarm not working, the circuit being cut, or damage to my own hearing. All are possible."

Im Doyun recorded that sentence exactly as it was. Jang Yura repeated it over the radio too. On site judgment uses the senses, but the senses can't be made king. That was the point where I was most likely to be wrong, more often than anywhere else.

I wrote in my notebook. Current floodgate test alarm: high pitched, immediate, strong wall reflection. Future South Gate memory: no alarm sound. Cause unconfirmed. Separating the missing item from Memory A.

Seo Jin looked at my handwriting. "This could be a record that works against you."

"I still have to write it down."

"That's better now."

That sounded like praise, so I didn't answer.

A small cursor blinked in the blank field at the bottom of the terminal. It looked like log corruption, but the technician didn't say so easily. Im Doyun made a request.

"Duplicate the original log. Include the blank field."

"That needs approval from above."

"This is evidence preservation."

"Authorization could get blocked."

"We record the process of it getting blocked too."

Seo Jin wrote that sentence down as well. The investigator's habit of sealing evidence was frustrating, but right now it had become a tool for pushing authorization through. The law is slow. Slow as it is, it leaves behind the point where things got blocked.

The technician pressed the duplication command. The progress bar stopped at 3 percent. The blank field at the bottom of the screen blinked once. Seo Jin drew in a breath.

"Now."

Im Doyun already had the camera up. "Recording the screen change."

The blank field appeared again, but the gray `proxy_token` line had disappeared. Where the clickable area had been, only empty space remained. The technician pulled his hand back and stepped away.

"I didn't erase that."

"That statement, recorded." Im Doyun said. "Field change during duplication. Party responsible for the manipulation unconfirmed."

Minchae spoke from behind. "The screen cache might still be there. In the screenshot memory."

"Is that possible?"

"If it's before the terminal shuts down. But if I touch it, that leaves a trace too."

Im Doyun thought for a moment. "The technician does a read only capture. Seo Minchae, procedural advice only."

Minchae bit her lip and nodded. It was frustrating to watch a scene she couldn't solve herself. But that frustration was the real pace of this case.

A phone rang. It wasn't mine. Im Doyun checked the evidence bag, and Seo Jin looked at her own screen. No caller ID. But the call was saved under my name. Before Seo Jin turned on the speaker, Im Doyun raised his hand.

Seo Jin's thumb stopped over the call button. She was a reporter, and a phone call was always something she answered first. This time, the manner of answering mattered more than the speed.

"Recording file name first." Im Doyun said.

Seo Jin read the file name out loud. Date, time, location, annex. Jang Yura turned toward the door. No one could be allowed to walk in during the call. The technician kept his hands visible without touching the terminal screen. Small movements gathered together to build the air before the call.

"Original audio recording. Capturing caller record. Call starting."

Seo Jin pressed the button.

A woman's voice came out. Short and dry. No metaphor, no greeting.

"That signature, I didn't press it."

My wrist stiffened inside the handcuffs. I knew that voice. Yun Seola. In the original timeline, the name of the traitor I'd been most certain about. The voice was lower than in my memory, and tired.

"Location." Im Doyun said.

Yun Seola didn't answer that. "You saw the blank in the audit log. If the executor field is empty, that's not direct manipulation. It's either a proxy token or a post hoc overwrite."

Seo Jin asked immediately. "How do you know that? That we're looking at that log right now."

A brief silence came. The sound of water dripping inside the drainage channel grew louder.

Yun Seola said. "Because right now, the only person who could be looking at that blank is Han Igyeom."

Seo Jin cut in right away. "That's not a source of information, that's a guess."

"It's a guess." Yun Seola answered. "But I know who's standing next to you looking at that blank right now."

"How."

"That field never shows on the public screen."

The technician's face went stiff. He reached to check the terminal settings again, then stopped. Because Im Doyun blocked him with his hand.

"Keep talking." Im Doyun said.

Yun Seola didn't laugh. "Not many people have permission to see that screen. And even fewer of them would actually go to the scene with that permission. Han Igyeom always wants to see it himself."

That sounded like intimacy, and at the same time like surveillance. I couldn't tell which one it was. I didn't say her name.

An old casual way of speaking almost slipped out of my mouth. Seola. I swallowed that name. If I said it now, memory would bury the evidence.

"Why did you contact me first." I asked.

"Because I was afraid you'd close the door just from seeing the signature."

"Where are you."

"Copy the original log first. Before the blank disappears."

The call cut off. No outgoing record remained. Seo Jin's recorder had been running, and Im Doyun's camera had been filming the call screen. But how Yun Seola had known about the blank in the current log left no trace at all.

Even after the call ended, no one spoke right away. Jang Yura moved first. "Keep duplicating the log. Trace the call separately. Right now we have to stop that blank from disappearing."

Im Doyun nodded. "Agreed on priority."

Seo Jin grabbed my arm. Not above the handcuffs, but the end of my sleeve. "You can't trust Yun Seola just because of what she said."

"I know."

"It's not only about not trusting her. It means don't use hatred as evidence."

That hurt more. I didn't want to trust Yun Seola. That was exactly why it was easier for me to make her the culprit. Seo Jin saw that.

I wrote a new line in my notebook. Yun Seola: denies the signature, aware of the blank, information source unconfirmed, denial of direct manipulation not yet verified. Below that I wrote the missing alarm sound separately. I didn't merge the two lines. Not yet. I couldn't merge them yet.

The cursor on the annex terminal blinked once and disappeared.