Detective Lee Seong-hoon spoke to Oh Moon-seong.

“The team in charge of the CCTVs around the bank is currently tracking down vehicles that passed through the area around the time of the interference. They’re planning to check dashcam footage as well.”

“Would someone who disappeared like a ghost really have walked along a busy road with cars passing by?”

“That’s what I’m saying.”

Oh Moon-seong let out a deep sigh.

“Sigh... So much for going home on time anytime soon.”

Seo Jung-woo walked along the street, patting his full stomach. As he wandered around exploring this world, he heard singing. It wasn’t someone singing directly but rather coming from a TV speaker.

“Is this song popular in this world right now?”

He listened to the upbeat tune for a moment and then smiled broadly.

“As expected, the songs from our world are better!”

In that world, the budget was prioritized for combat equipment production and defense infrastructure. As a result, costly cultural industries couldn’t properly develop. Large-scale entertainment facilities like water parks, which required significant construction costs, had already been destroyed long ago.

That didn’t mean people gave up on entertainment.

Music could still be enjoyed just by banging on tin cans to create rhythm. That world had developed a thriving culture of entertainment that required little money.

Seo Jung-woo envied this world’s peace, its abundant resources, and even its beef and cola. But when it came to music, he regained a bit of pride.

“Our world's music is definitely much better.”

He shrugged his shoulders and walked toward the source of the music. Turning the corner of a building, he found a store with a large TV turned on.

“Oh…”

That world also had a well-established TV broadcasting system.

TV was used as an information channel, a means of policy promotion, and a way to fill the void left by the lack of entertainment. It also served as an emergency alert system when necessary.

However, as he watched the TV here, the pride he had regained through music diminished slightly.

“The people here are prettier.”

On TV, a girl group was performing a song.

He still believed the music from his world was superior, but he had to admit that the girl group’s beauty was undeniable.

“Wow, they’re dazzling. Every single one of them is so pretty.”

The song soon ended. A host appeared on the late-night music program. Even though it was daytime now, the show was a pre-recorded cable TV broadcast.

“Wow. That Hunter is here too?”

That world also had the same host. However, in that world, he had awakened combat abilities and became a Hunter who fought monsters—all while continuing his music career.

“Same person, but the atmosphere is completely different…”

Realizing something he had overlooked, Seo Jung-woo was startled.

“If that person exists in both worlds… then what about me in this world?”

His original plan was to lay low and enjoy this world for 24 hours. Since he had already fired four shots at the bank, he intended to stay out of trouble for the rest of his time here.

But the situation had changed.

“I was planning to gather information the next time I came back, but I can’t just ignore this now.”

He decided to change his plans. Before he enjoyed his time here, he needed to check on the Seo Jung-woo of this world.

His house was far away. There was no way the bus routes would still match.

“Why are the buses only running in the middle of the road? The buses seem to have changed a lot, but at least the subway routes should be the same.”

Seo Jung-woo found the nearest subway station and went inside.

“Lines 3 and 4 are still the same as before, thank go—Wait, they got longer! Oido? Why is Line 4 going all the way to Oido?!”

The subway network had expanded significantly since his time.

The central parts of the subway system still matched between the two worlds. Everything that had been completed by 1999 was the same.

But after that, the other world couldn’t expand its subway further. Fighting monsters was costly enough, and even maintaining the existing subway required substantial resources. Instead of building new subway lines, they had spent the money on constructing shelters.

Seo Jung-woo looked around the station. There were no heavily armed subway guards.

The fare payment system was different, too. There were only ticket vending machines.

Even so, buying a ticket wasn’t difficult. He simply mimicked what others were doing. He was a bit surprised when a card-type ticket came out instead of the yellow paper tickets he remembered.

Seo Jung-woo went down to the platform. Shortly after, a train arrived.

“Wow. There’s not a single armored plate on this train.”

In that world, subway trains had ramming armor plates on the front. If a conductor spotted a monster on the tracks, they would plow through it with the sharp horns on the front of the train. The trains also didn’t rely on electricity from the tracks but had their own power sources.

The subway system in that world had been heavily damaged during the initial monster invasions. When they rebuilt it, they installed defense mechanisms everywhere. Heavily armed subway guards patrolled frequently.

Subways were risky when attacked by monsters since there were limited escape options. Fares were also incredibly expensive. Almost no one used them for daily commutes.

While regular people weren’t outright banned from using them, in that world, subways were mainly used by Hunter teams, military units for tactical movement, and for transporting supplies.

He took the subway north on Line 4 and got off at a station. The station looked quite different from what he remembered. A blue dinosaur cartoon character was painted on the walls.

Outside, there weren’t any skyscrapers as tall as the ones in Yongsan, but there were still several high-rise buildings.

“It’s really changed a lot.”

He walked through the residential area toward where his house should be.

“At least the roads haven’t changed much.”

The roads were the same, but the houses were different. There were no barbed-wire fences, no steel bars over the windows, and no reinforced shutters.

Seo Jung-woo arrived at his old address. The house looked mostly the same as he remembered.

“If my family still lives here, then that means I should be here too…”

The front gate suddenly rattled open, and Seo Sora stepped outside.

Seo Jung-woo was startled.

“Huh?”

Seo Sora scowled.

“What? What’s with that look? Are you here to start something again?”

“Uh… Right, you were born in the 20th century.”

The world had changed drastically due to the monster invasion on January 1, 2000. Seo Sora had been born before that.

Seo Jung-woo tensed slightly and asked,

“Are you sure you recognize me? Nothing seems… off to you?”

“What are you talking about? Are you crazy?”

Seeing Seo Sora's natural reaction, he became certain.

‘Seo Jung-woo exists here too.’

However, the Seo Sora of this world felt very different from the one in his world.

“Sora, what are you doing these days?”

“Doing? Are you making fun of me for being a lifelong trainee? I'm telling Mom!”

“Training? Are you talking about skills?”

“TOEIC skills?”

“Huh?”

“What are you even trying to say?”

“If it’s not skills, then what are you training for?”

Seo Sora furrowed her brows even more.

“Ugh. Are you teasing me again about when I'll finally debut as an idol?”

Seo Jung-woo was genuinely taken aback.

“Huh? With your face?”

“I’m aiming to be a talented singer, not just a pretty face! And you’re not in a position to talk about looks, are you? Let’s not throw stones at each other, okay?”

Seo Jung-woo realized their conversation kept going in different directions. He decided to ask a different question to gather more information.

“Ah, never mind. So where are you going?”

“To school, obviously.”

“Oh. School. Huh? Wait, you mean university?”

“What other school would it be?”

“What year are you in?”

“Third year, duh!”

The Seo Sora of this world was a university student dreaming of becoming an idol, while his younger sister in the other world was a sniper.

When Seo Jung-woo kept saying strange things, Seo Sora finally exploded.

“You kept telling me I’d never make it as a singer no matter how much I trained, so I should study hard and at least go to college! So I did! Why are you picking a fight now?”

“Oh. I’m just impressed?”

Seo Sora glared at him.

“Are you just looking for a fight today? Huh? Wait, what’s up with your clothes? They’re completely different from when you left this morning.”

He gained new information.

‘Her personality is different. Is it because of her environment? That makes sense. This girl grew up in a peaceful world, while my sister trained in long-range surveillance skills since childhood to become a sniper. Ugh, my poor sister. She should have been able to live comfortably and abundantly like this.’

Seo Jung-woo’s eyes welled up.

‘She should be able to put on makeup like her… Huh? Makeup must be common here?’

Even in his world, makeup was still produced. However, the supply was limited, making it expensive. That was because military factories had replaced cosmetics factories.

In his world, many people mixed ethyl alcohol with glycerin to use as lotion. Ethyl alcohol and glycerin were byproducts of military production and thus easy to obtain.

Seo Sora narrowed her eyes and examined him.

“Seriously, what’s wrong with you? What happened? And now that I look closely, those aren’t even new clothes. You look like you picked them up off the street.”

At that moment, Seo Jung-woo saw the same look on her face that his sister made when tracking monster traces in the other world.

‘Ah. She…’

Though their personalities and speech were different, their expressions were identical.

Seo Sora hesitated for a moment, then asked in a slightly concerned tone.

“What is it? Did they give you a hard time on your first day at work?”

“Huh? Work?”

“You said you were starting at a new team today.”

Seo Jung-woo gained new information.

‘The Seo Jung-woo of this world isn’t home right now. That means he went to work. I should go there and gather information about him.’

“Sora, where do I work?”

Seo Sora suddenly turned toward the house and shouted.

“Mom! I think my brother's gone crazy!”

“Ack!”

‘Mom? In this world?’

“Mom and Dad are on an overseas assignment in Europe. Why do you look so shocked? Are you super stressed about work or something?”

“It’s a joke. Just a joke. So, where exactly am I working…?”

Seo Jung-woo arrived at the police station.

He didn’t go inside immediately. Instead, he stood in the parking lot, deep in thought.

“So, the Seo Jung-woo of this world is a police officer.”

He hadn’t been able to get much information from the suspicious Seo Sora. He had barely managed to learn the name of the police station.

“But in such a big station, how do I find him?”

Just then, a group of detectives came out of the building. Seo Jung-woo turned to look at them and then at the building across the street.

One of the detectives, Baek Sung-min, stopped walking and tilted his head at him.

“Huh? Seo Jung-woo?”

Seo Jung-woo quickly turned toward him. He didn’t recognize the face. But the other person clearly knew him.

‘A chance to gather information!’

“Yes. I am Seo Jung-woo.”

‘At the very least, I need to figure out which department he works in.’

Detective Baek Sung-min let out a deep sigh.

“Oh, come on. ‘Yes, I am Seo Jung-woo’?”

“Yes?”

“Team 1 is already swamped with that bank robbery case, and now the rookie didn’t even show up on time? And not just a little late, but in the afternoon? And now what?”

Seo Jung-woo gained new information.

‘So, the Seo Jung-woo of this world didn’t show up to work?’

Of all days, his counterpart hadn’t come in on the exact day he crossed dimensions. This didn’t feel like a coincidence.

“Do you know why he didn’t come in?”

“How the hell would I know? That’s your job to figure out!”

“Ah. That makes sense.”

“Where the hell did they send this lunatic from?!”

Team 2 leader Kwon Byung-chul spoke up.

“Hey! We don’t have time for this. Just get the rookie in the car too!”

The detectives all piled into a van.

Seo Jung-woo needed information. So, he got in as well and asked Baek Sung-min a question.

“By the way, how do you know me?”

“How would I know a guy who’s starting today?!”

“But you recognized me at first glance.”

“Because we got your photo beforehand. Isn’t that obvious?”

“Ah. A photo.”

“Ugh, this guy is seriously something else. As soon as we get back, I’m returning you. Consider yourself warned!”

Team 2 leader Kwon Byung-chul spoke.

“Sung-min, if we don’t catch the ‘24-Hour Serial Killer’ within 24 hours, we’re all getting disciplinary action, not just the rookie. Focus on the case.”

Seo Jung-woo heard a familiar name. He was shocked.

“The 24-Hour Serial Killer?”

Baek Sung-min looked at him in disbelief.

“You don’t even know that? Why the hell did you join Major Crimes?”

“I do know. The culprit kidnaps victims and sends photos, right? Along with a message saying there are 24 hours left. After 24 hours, the victim is killed. That’s why they’re called the 24-Hour Serial Killer.”

“Then why are you so surprised?”

Seo Jung-woo wasn’t shocked because he didn’t know.

‘That guy was caught last year.’

In his world, the 24-Hour Serial Killer had already been apprehended.