After Im Seoha's Account Changed to Checkout Complete, the Shuttle Phone Called the Librarian's Name in a Child's Voice

After Im Seoha's account changed to checkout complete, the shuttle phone called the librarian's name in a child's voice.

Ryu Eunchae did not give her own name.

At 7:23, the vehicle sat parked at the end of the library's south ramp. Past the closed door, the library's outer wall was visible, and the staff stairwell door still read 8 degrees on the field camera feed. The citizen liaison beside Eunchae was checking the cancellation contact list for the school tour. At the center, Seoha still had her face and name intact, but her account number had been swapped for a lost book barcode.

The call did not come in through the library's main line. The vehicle's shared facility terminal rang first, and the same caller ID appeared in the center's queue a beat later.

Eunchae locked the vehicle door before answering. She cracked the window two centimeters to keep the field radio audible, and routed the call's output not to the outer speaker but to the handset between the seats. She started by limiting who could hear a name because of her own choice.

When she pressed answer, the familiar library hold music played. It was the four-bar piano piece used for the automatic announcement before closing.

The four bars ended, but the music did not stop.

A low voice sang a fifth measure.

"Put the book down. Go to your seat."

Eunchae did not log it as a child's voice. She sent Yuna only the observation that the pitch was high and the pronunciation short. In the next moment the voice asked.

"What's the librarian's name?"

The citizen liaison looked over at Eunchae. No one at the center answered in her place either. Mijin left open the button that would transfer the call from the vehicle to the center, but didn't press it.

Eunchae did not offer a greeting meant to soothe the caller. "Where you are right now, which direction does the handle on the book slot move to open?"

The voice answered immediately.

"Pull it to the right."

Wrong.

The children's return slot beside the reading room had no pull handle. When a book was placed on it, a weight sensor read it and the inner panel slid three centimeters. The outdoor collection box by the back door had a handle, but it had to be lifted up.

There was one more handle in the building that pulled to the right.

Eunchae didn't state the conclusion first. She had the facility floor plan and pre-closing inspection photos opened separately on the center's screen. On the floor plan, the low return box in the half basement boiler pipe room was labeled "waste paper collection box." It wasn't equipment for receiving library books, it was a steel box for putting in old inspection sheets and filter wrapping from the corridor side.

That box's handle pulled to the right.

Mijin tried to change the screen status from "reading room call" to "pipe room candidate." Dowon sent two radio confirmation tones first.

"Candidate only. Don't put it on the dispatch assignment."

Mijin stopped her cursor. Pressing "change location" would automatically attach pipe room entry to the field team's work order. She left the status value untouched and made only a candidate line in the knowledge ledger. She didn't pass the cost of opening a door onto the field just because the center had found a location.

"What's the height?" Eunchae asked.

Instead of laughing, the voice knocked on something twice. "Below the knee."

"When you open the door, which corner touches first, and where is it dented?"

This time the answer came late. The hold music came back in. After four bars, the fifth measure overlapped on the same note. Eunchae did not approve the melody's repetition as a real child's memory. Yuna laid the waveforms of the first and second playback side by side, and flagged only the section where the ending breath matched exactly as a possible automated audio source.

The voice said. "Lower left."

Eunchae shook her head. On the low return box, it was the upper right corner that was folded inward. It was a mark left three years ago when someone had forced a filter box in. Eunchae had attached a photo to the facility inspection sheet, and the mark had remained even after it dropped out of the repair budget.

"That answer is wrong." Mijin said.

"The direction is right, the corner is wrong." Eunchae corrected immediately. "We still don't know if it read the pipe room or just the floor plan."

Eunchae didn't leave her own memory as the sole evidence. She showed the shooting date and her own signature on the back of the inspection photo first. In the pre-closing exterior shots the field team had, the corner of the box on the corridor side appeared small. The two photos captured the same mark from different angles, but both came from files in the library's storage network. Yuna attached the qualifier "different angles, same storage source."

The citizen liaison didn't press the send button on the school contact list, and instead showed Eunchae the screen. The draft read "confirmed transmission location: boiler room."

"It's not confirmed." Eunchae said. "It's only that pipe room has become more likely than reading room."

The liaison revised the sentence to "access to entire library area remains restricted / south ramp passage available / transmission location under confirmation." She didn't add the phrase about the call mimicking a child's voice, or the librarian's name. This let the school keep choosing to cancel the tour and maintain the restriction without being handed the fear directly.

"Don't attach my name to this call either." the liaison said. "I'll confirm with the school by role."

Eunchae didn't approve that choice on her behalf. The liaison left only her own duty number and the vehicle's location with the school, and reconfirmed the tour cancellation for the next day. The citizen contact network never became bait for finding the caller, and the actual safety action never stopped either.

The field team did not enter the building. Dowon didn't push the duct camera in the staff stairwell gap any further, and instead placed a contact microphone against the boiler intake vent on the exterior wall. Another team member attached the same kind of microphone to the outer frame of the back door return slot. The center did not merge the two channels into one file.

Eunchae asked the call. "When you let go of the handle, what moves first on the inside?"

"A book falls."

If it were the reading room return slot, the center teaching aid sensor would turn on first and the roller would spin. If it were the back door collection box, the metal cover would close and then touch the tray. In the low return box in the pipe room, there was no space for a book to fall. Behind the shallow box, a vertical gap met the boiler pipe inspection port.

The floor plan alone couldn't tell what sound that would make inside.

Eunchae asked one more ordinary flaw she had seen with her own eyes. "Don't touch the upper right corner, just look. Under the folded steel plate, what color remains?"

Metal scraped behind the voice.

"Green."

Eunchae zoomed in on the photo. Under the folded coating wasn't green rust preventive, it was gray zinc plate. But the heating pipe running under that corner was wrapped with a green flow marker. It wasn't visible from outside the box, only visible when the pipe room's inner inspection port was open.

The voice wasn't looking at the return box.

It was looking at what was behind the return box.

Three metal scrapes came into Dowon's intake vent microphone. They arrived two seconds later than the scrapes in the call. The back door return slot microphone only picked up roller vibration, no metal scraping. It still wasn't known whether the center's delay was consistent, but of the two outside channels, only the pipe room intake vent picked up the same kind of sound.

Seoha didn't use the "checkout complete" status on her account as authorization to enter the pipe room. Leaving the first ticket's 4721 and her current face on the screen, she only read the timestamps of the call, the intake vent, and the back door microphone. "Two seconds after the call. Don't fix the location from one instance."

Dowon tapped the intake vent screen once with the handle of a rubber mallet. The same sound didn't come back from the call side. Only the pipe room microphone received the vibration immediately. Whether the sound was being duplicated in one direction, or was simply a transmission delay, was still undetermined.

Mijin didn't tell the field team to open the pipe room door. "Only change the location candidate. Don't finalize excluding the reading room either."

Dowon answered. "Maintaining field refusal. Observing heat and sound only from outside the vent."

In the past, the moment the center's assignment screen changed to "pipe room confirmed," the field team would have gone straight for the door. This time, Dowon's refusal went into the ledger not as delay or insubordination but as a verification method. Eunchae's location questions and the field's no entry measurements were laid side by side on the same line.

Eunchae gave neither her own name nor Seoha's to the call. "Which direction does the arrow on that green marker point?"

"Down."

In the inspection photo, the green marker ran horizontal from the boiler toward the exterior wall. A green marker pointing downward wasn't in the library's floor plan.

Eunchae didn't retreat back to the reading room after seeing the wrong answer. She split the possibilities: either the marking had changed, or another facility's piping had overlapped it. Yuna separated the call's answers into two columns, "matches library pipe room" and "not in the library."

The fifth measure played for the third time.

This time, a short electronic tone slipped in between the audio and the voice.

Beep, beep, one long beep.

Eunchae recognized the sound even with the vehicle handset away from her ear. The library's boiler sounded the same pressure alarm three times, short. Two short and one long wasn't on Hanbit Library's equipment list.

Dowon lowered the sensitivity on the intake vent microphone. Two seconds after the electronic tone sounded again in the call, the same interval came into the exterior pipe room microphone too. There was none at the back door return slot.

The center's equipment comparison table automatically brought up a candidate. Even after reading the first search result, Eunchae didn't name the facility. Mijin checked the manufacturer's manual, the current public facility alarm list, and actual unreported faults separately.

Two short, one long.

That pattern was the low temperature alarm for the heating circulation pump in the city hospital's annex building.

Mijin didn't ask the hospital's night duty room for a name, she asked about the circulation pump indicator light in the annex and its next automatic action. The reply was a green operating light, a standby backup pump, and no current alarm. There was still no matching sound at the hospital site. Only the manual's pattern matched.

Eunchae wouldn't let the ledger title be written as "hospital heating alarm." She left three conditions on one line: "library pipe room acoustic / matches hospital equipment alarm pattern / not occurring at hospital site." The library's piping wasn't connected to the hospital either.

The only thing confirmed now was that a hospital alarm sound not present at the library was being heard in the library's boiler pipe room.

The voice on the phone asked again.

"What's the librarian's name?"

Eunchae did not put down the handset.

"Instead of the name, check the color of the next valve."

Instead of an answer, the hospital heating alarm sounded a fourth time.