He looked around in bewilderment.
He remembered exactly how he had swung his sword just moments earlier, but he could not understand how that single strike had brought the situation to an end.
'Is this a skill that comes with the sword?'
He looked down at the Ghost-Observing Blade.
He had experienced more than enough to know that his physical abilities improved the moment he held this Joseon-era saber.
But this time, his attack had reached far beyond the range he had expected his sword to cover.
A word suddenly crossed his mind: 'Sword Energy.'
It was something he had encountered only in martial arts novels and fantasy stories.
It seemed impossible, yet the severed railing lying at his feet left him at a loss for any other explanation.
The people watching the scene from the office were just as astonished.
“Did he just release Sword Energy?”
Manager Bang Ji-seok muttered, tilting his head.
Department Head Cha Jun-ho did not answer, but he had seen something similar before.
They were techniques the founding chairman had used when performing exorcisms.
'It really does run in the family.'
A smile spread across his lips.
* * *
Having finished inspecting the entire second floor, Tae-woo hurried out toward the school gate.
When Seung-hoon saw him, he immediately got out of the driver's seat.
He could not conceal his surprise at the sight of Tae-woo, who was covered in dust and sweat.
“Young Master, what on earth happened to you—”
“—Drive. Drive. Drive. Just drive, please!”
Tae-woo shouted as he scrambled into the back seat.
Seung-hoon shrugged, cast one last glance at the dark, abandoned school, and climbed into the driver's seat.
VROOOOM—
Then he drove off at once.
Tae-woo lay half-reclined in the back seat, panting, before finally taking off his smart glasses.
“Did something serious happen inside? How did you get so filthy?” Seung-hoon asked as he drove.
“Huff, huff. Ghosts. It was the ghosts.”
“You saw ghosts, and that's why you ended up covered in dust?”
Seung-hoon looked at him through the rearview mirror, sounding surprised.
“They're terrifying no matter how many times I see them. Ugh.”
Tae-woo answered, pressing a hand to his chest. Then his eyes widened, and he asked another question.
“Wait a minute. Do you know all about Gwihon Trading, too?”
It was a fundamental question.
“Of course I do. I was the one who drove the founding chairman right up until shortly before he passed away.”
“Then you knew there were ghosts in that abandoned school?”
“Yes, I know that very well. The Cleanup Team uses it as a field orientation site for new recruits. Although this was my first time going there myself.”
Seung-hoon spoke as though it were nothing out of the ordinary.
Tae-woo privately felt a little resentful that Seung-hoon had not warned him, but he did not dwell on it.
“Then can you see ghosts, too?”
“No. I don't have Spirit Sight.”
“...Really? But, uh, then how were you able to work as my grandfather's driver...?”
“When you're driving, it's better not to be able to see ghosts.”
Seung-hoon's answer left Tae-woo speechless.
After all, there really were quite a few ghosts on the roads, people who had died in traffic accidents.
Seung-hoon continued.
“Besides, the founding chairman saved my life. That's how I came to work for him.”
“My grandfather saved you?”
“Yes. You know about Death-Calling Ghosts, don't you?”
“Death-Calling Ghosts? Oh! Yes, I do!”
They were Grade 2 ghosts described in the Ghost Observation Record.
A higher class of ghost than the common Grade 1 Mountain Ghost, they could induce auditory hallucinations and drive people toward suicide or murder.
“After my wife took her own life because of financial hardship, she became a Death-Calling Ghost and tormented me every day, telling me to follow her. It was the founding chairman who put an end to it. It's already been ten years.”
Seung-hoon looked at Tae-woo through the rearview mirror as he spoke.
“My grandfather took care of it?”
Tae-woo wanted to hear more, but Seung-hoon merely smiled without elaborating.
“I'll take you straight home.”
Instead, he announced their destination and smoothly changed the subject.
* * *
As soon as Tae-woo arrived home, he connected his smart glasses to his computer without even changing his clothes and checked the footage he had just recorded.
Just as he had suspected, the ghosts were invisible to the camera until they became aware of Tae-woo. Only then did their figures appear in the recordings.
As a result, every clip was frightening, like a sudden jump scare.
“This should be good enough.”
Watching the footage brought back the unpleasant feelings he had experienced at the school, but he endured them and transferred the recordings onto a memory card.
Then, without delay, he set to work on the radar and flashlight integration projects he had written down in his notebook.
Working without rest like this was simply in Tae-woo's nature.
Once he had a goal in mind, he became utterly absorbed in the task, to the exclusion of everything else.
That tendency was especially pronounced when he worked with information technology or machinery.
First, integrating the flashlight was not particularly difficult.
All he had to do was attach it directly to the smart glasses as a built-in component.
However, because the flashlight emitted such a powerful beam, he had to choose its angle carefully to prevent the light from shining into the camera lens.
He also remembered to configure the display so that the flashlight's remaining battery charge would appear on the smart glasses.
Then came the radar project.
As he worked, Tae-woo gave it the name 'Ghost Radar.'
The principle behind it was simpler than it might sound.
He intended to turn the momentary interference ghosts caused in electronic devices to his advantage.
His smart glasses were electronic equipment as well, and they were sensitive to the effects of ghosts. In fact, the user interface had occasionally distorted whenever a ghost appeared.
Until he identified the wavelengths or signals through which ghosts interfered with electronics, there was no way to prevent that problem.
In any case, if he transmitted a particular radio signal into the surrounding area and a ghost capable of disrupting electronic devices was present within its range, that ghost would surely register as an anomaly in the signal.
And the stronger the interference, the more clearly he ought to be able to detect it.
At the most basic level, stronger interference would suggest a more powerful ghost. In theory, the radar might even let him locate an especially dangerous ghost before it appeared in front of him.
He looked over the electronic devices displayed on his shelves, and his gaze settled on the Bluetooth products.
It occurred to him that Bluetooth might be useful for putting his idea into practice.
Ever since Bluetooth earbuds had become commercially available, he had experienced brief interruptions in their connection when he encountered ghosts while walking down the street and listening to music.
Whenever the Bluetooth connection cut out for a moment during an ordinary walk, he would look around and invariably find a ghost nearby.
Besides, Bluetooth signals could reach roughly twenty meters. If he could make good use of that range, they would be ideal for a short-range radar.
“There are devices that can track locations using Bluetooth.”
He got up, brought over his phone and earbuds, and began taking them apart.
After extracting the Bluetooth module, he equipped it with a distance-measurement function called 'HADM.'
It was not an easy task.
Technology for tracking locations using Bluetooth already existed, but employing it for this purpose and integrating it into the smart glasses' user interface was something no one had done before.
Yet Tae-woo knew exactly what he wanted to achieve. With soot still smeared across his face and clothes, he worked through the night without stopping.
Three days later.
Tae-woo was sprawled facedown among a jumble of components and tools, snoring loudly.
BZZZZ— BZZZZ—
His phone kept vibrating at perfectly regular intervals, but he showed no sign of waking.
Only after several missed calls had accumulated did he finally stir, pick up the phone, and hold it to his ear without even looking at the screen.
“Mmm... Hello?”
[Senior Associate Kim Tae-woo? It looks like you've completed the assignment we gave you, so why haven't you come to work?]
It was Assistant Manager Yoon Ye-rim's voice.
The instant he heard her, Tae-woo's eyes flew open, and he checked the date and time.
“Ah! Oh, yes, yes. I'll come in right away.”
He had been so absorbed in his work that he had lost track of time and had not even realized three days had passed.
He sprang to his feet and rushed into the bathroom.
* * *
Gwihon Trading headquarters, Gangnam District, Seoul.
Tae-woo hurried into work with his hair still damp. After taking the elevator and completing the identity verification process, he went straight to the fourth floor.
[Fourth floor.]
As soon as the elevator announcement sounded, Tae-woo hastily gathered his belongings, stepped out, and headed for his desk.
Along the way, he awkwardly exchanged greetings with everyone whose eyes he met.
“You're here?”
Assistant Manager Yoon Ye-rim, who had been busy working, poked her head over the partition.
“Ah, yes. Yes.”
After sitting down, Tae-woo immediately checked the clock.
It was eleven o'clock, a full two hours past the official starting time of nine.
He was late.
“Senior Associate Kim, you're supposed to come back to work as soon as you finish your field recording. What have you been doing all this time?”
Manager Bang Ji-seok stood up and glared at him.
“Ah, I-I'm sorry. I was upgrading the equipment I used for the recording.”
“Upgrading your equipment? You mean those strange glasses you were wearing out in the field?”
“Yes, yes. Those—wait, how do you know about them? Did you see them?”
Tae-woo began to answer, then looked at him in confusion.
He had assumed that no one at the company knew he had been using smart glasses.
Just then, Department Head Cha Jun-ho emerged from his office and spoke as he headed toward the conference room.
“Team Four. Conference room. Now.”
At those words, Manager Bang Ji-seok and Assistant Manager Yoon Ye-rim sprang to their feet.
Seeing Tae-woo's puzzled expression, Yoon Ye-rim motioned for him to get up as well.
“We're Team Four. Cleanup Team Four. The fourth team in the Cleanup Team.”
“Ah, yes, yes.”
Tae-woo hurriedly picked up his notebook.
“Bring the memory card with the footage you recorded.”
“Ah, yes!”
At Manager Bang Ji-seok's additional instruction, Tae-woo quickly grabbed the memory card too.