Despite the lackluster appearance of the outside of the building, the interior was incredible. Taehyung stared wide-eyed at all the scientific gadgets and apparatus around him as he followed the group through a large room filled to the brim with loads and loads of stuff. He wanted to look more closely at thing things around him, but he was concerned that he'd end up touching something, breaking it, and causing a massive explosion. Taehyung couldn't very well get home if he'd blown himself up. The scientist, who was currently full-on ranting about various things to anyone that would listen, was also preventing him from stopping, as he was walking so fast the boys that were politely walking close to him had to speed walk to keep up. With a smile, Taehyung realized that Yoongi was unsuccessfully trying to explain the situation on their part to the scientist, but the older man seemed to want to rant out his rage about anything and everything first.

Taehyung's jaw dropped as the scientist lead them into a huge, dark room with strange machines whirring and lights blinking. It looked straight out of a television show or movie, like The Flash. Even the other boys seemed amazed as they looked around.

"Sir, who are you-" an unfamiliar male voice cut itself off. Taehyung looked around to see a boy around his own age standing in the middle of a large doorway that seemed to lead into a different hallway than the one they had entered through. The boy had his arms full of what appeared to be books and documents. His eyes narrowed when he saw the group. "Oh," he said, obviously unhappy.

Taehyung sensed a change in the scientist's mood then. "Joshua," the man said cooly enough. Perhaps too cooly. "These boys are here for help."

"Help?" Joshua huffed, holding the many books up higher and storming into the room. "What kind of help would people like them want here?"

If the other boys hadn't been offended before, some of them certainly were now, judging by the skillfully controlled rage on their faces. Still, something happened that surprised Taehyung. Joshua stumbled forward, still looking angry, then just as he passed by, he tripped and the books and papers went flying. Whether it was out of actual concern or just force of habit, Yoongi reached out to catch the boy. The moment his hand touched Joshua's back, however, the boy seemed like he had been given an electric shock. He jumped away and yelled loudly, causing even the old man to pause and look at him.

"What is it now, Joshua?" he asked, obviously exasperated.

Joshua was glaring daggers at Yoongi, who looked like he was about to explode. "He touched me," Joshua said.

"Well then," the man said, "consider yourself lucky. Most people would have to pay for that."

The boy looked outraged, almost as much as Yoongi. He looked at the scientist and Yoongi, then stormed out of the room, leaving his books and papers a scattered mess on the floor.

The man almost half smiled as soon as Joshua left, then looked at the remaining boys with a far more pleasant expression. "Don't pay that idiot any mind, you boys." He scoffed. "I never even wanted that one around. The first one was far better and much less judgemental. And don't you boys worry about speaking formally to me, I don't really give a damn and I won't tell your bosses."

A few of them seemed relieved by this news, the others still looked angry. Taehyung was curious. "If you don't like him, why is he here?"

The man turned away with another scoff. "Oh, rich people, you know. You see, there were two candidates to be my assistant here. One of them was a middle-class boy. Very smart. Respectful. I liked having him around. But then His Royal over there got mad and complained to his CEO father, and the next thing I know, I have to kick the first one out onto the porch and replace him with that one. Ridiculous, I tell you."

"Why did you have to replace him?" Namjoon asked. "I thought you were funded through a university."

The man let out a sad laugh. "I started working for the government a few years ago. Not voluntarily, I'll have you know, they forced me to turn my studies to power their war machine."

"The nuclear war," Hoseok said.

The man nodded solemnly.

"We're all going to die, aren't we?" Jeongguk asked softly.

The man nodded again. "The end of the world as we know it is coming fast," he said. "And the most damning thing about it is it could be prevented."

Taehyung's heart sank at the downtrodden expressions on their faces. Still, he selfishly worried about what would happen to him. If this man couldn't help him, then he would be stuck here, and would die here. If this man could help him, and he somehow could get home, then he would be forced to leave these boys here to die.

He didn't like either of those options.

"So, if we're all going to die soon, I don't suppose you would mind committing treason?" Yoongi asked.

The man sputtered. "Excuse me? Treason?"

"Yoongi!" Namjoon and Seokjin yelled out simultaneously.

The black-haired boy looked at them. "What?" he asked. "In case you can't tell, we don't have forever. We need to get Taehyung back where he belongs."

Hoseok sighed, shaking his head. "Did you not just hear that he works for the government? We ain't getting nowhere if we get arrested and those two-" he pointed at Namjoon and Jeongguk- "get... you know."

Jeongguk shivered and wrapped his arms around himself. Seokjin slapped Hoseok's arm.

"Excuse me? What the hell do you mean, treason?" the scientist half-yelled.

Yoongi turned to him again. "You see, Taehyung here is from Korea."

The man's jaw fell open.

"Yoongi!" Seokjin yelled again.

"But not Korea as you know it."

Taehyung could practically see the gears in the man's head rapidly spinning as he began glancing between Taehyung and Yoongi. Slowly, he reached towards a nearby desk, and Taehyung feared that he was going to sound an alarm and it would all be over. But instead, he grabbed a chair and slowly set himself down.

"My name is Halkyeon. And you boys better tell me what is going on."
 

In the next few hours that followed, Taehyung and the others told the story of the two worlds. Halkyeon was surprisingly calm throughout the whole story, and listened well, only interrupting to ask an occasional question. When the tale ended with "and we were hoping you could help," he didn't say something for a long time, but had a curious wonder in his eyes.

"There is something," he said after a while of silence. "Something very few physicists talk about. A theory." He spun his chair around and pulled out a rather complicated-looking computer and typed at a rapid-fire pace.

"A theory of what?" Hoseok asked.

Halkyeon smiled. "A mirror universe theory. Taehyung, would you mind if I took a sample of your blood?"

"Um," Taehyung replied. "Why?"

The scientist's smile widened further as he saw something on the screen and spun his chair away, practically skipping to a nearby cabinet. "To see what you're made out of!"

Taehyung watched as the man rummaged through a drawer. "Okay, I'm not the toughest guy, but I don't think you need to take my blood to