Sinner's Prison: Korea University Central Library, Reading Room 1
The prison for guilty college students—Korea University Central Library, First Reading Room. Forgetting the sun rising and setting outside the window, I was buried in a mountain of books.
"...The problem was the sulfur (S) and phosphorus (P) content. In the fantasy world's pig iron, the impurity removal process is a total mess, causing hot shortness where the iron tears apart at high temperatures."
My eyes were shot through with bloodshot veins, but my lips kept muttering nonstop, voraciously devouring knowledge. The moment I returned to Kang Woojin's body, I didn't eat or sleep. I bolted straight to the library and dove headfirst into textbooks on metallurgy, materials mechanics, and metal engineering like a madman.
"To catch these impurities, you gotta slam limestone into the furnace to make basic slag. Then add manganese (Mn) to neutralize the sulfur. Yeah, that's it!"
Bam! In my excitement, I slammed my fist on the desk, startling the other students studying nearby into staring at me. But I couldn't care less about their gazes. In that other world, the boiler I'd built might be teetering on the brink of explosion right this second.
I had no idea how time flowed there, but if even a minute or a second passed the same, Aila and the factory were probably already reduced to ashes.
'But judging by the sensation when the pendant activated, time over there must be practically stopped or flowing excruciatingly slowly while I'm here. Otherwise, this miracle of traveling between worlds wouldn't hold up.'
Even so, I couldn't relax. To prevent the explosion and forge a perfect boiler that could withstand that insane steam pressure, I had to completely shatter the limits of materials.
"Steel plates for pressure vessels need low-carbon steel with less than 0.2% carbon to maintain toughness. Alloy it with trace amounts of chromium (Cr) and molybdenum (Mo), and you get heat-resistant steel that can handle high-temperature pressure."
Refining rare metals like chromium and molybdenum right away in the fantasy world was iffy, but I crammed in the characteristics of substitute ores and smelting methods too.
"Next up: the joints where the steam leaked. Leather and grease? No way in hell."
In the modern world, you'd just use Teflon or high-performance synthetic rubber O-rings, but the fantasy world has no petrochemical industry.
"Graphite it is. Layer graphite powder with thin copper sheets to craft metal-graphite gaskets that endure high heat and pressure. That'll seal steam at 400 degrees Celsius perfectly!"
Scribble scribble! I filled the notebook until the mechanical pencil lead snapped. A perfect master plan was taking shape to transform the fantasy world's crude iron lumps into immortal steamships that could conquer the seas.
Gurgle rumble—
Then, thunder rumbled from my stomach. After days of surviving on canned coffee and triangle kimbap, my gut was screaming.
"Hah, gotta stay alive first."
As I rolled my stiff neck and stood, my smartphone in my pocket chimed with a short ding—.
"Ah."
I let out a short sigh. Money. In this world or that one, it was always money tripping people up.
Korea University tuition was murderous—on par with a decent Peluah trading company's annual budget. Sure, I was Carnoble's heir with some wealth back in Peluah, but Kang Woojin's bank account was pathetic, barely enough for a few ramen packs.
'Luckily, all that life-or-death studying last semester paid off big time.'
Right after possession, I'd absorbed mechanical engineering knowledge like a maniac. The perennial academic probation candidate Kang Woojin's transcript was now plastered with A+'s and a monstrous 4.5 GPA. That snagged me full national scholarship coverage, wiping out tuition worries.
"The problem is having to carve out precious time to sign those damn papers in person."
Bureaucracy's a pain everywhere. But when in Rome, do as the Romans do—or when at university, follow university admin rules.
I hugged my notebook close, roughly swept back my matted hair, and left the library.
Mechanical Engineering Department Office.
Opening the door unleashed a blast of printer toner and stale coffee scent.
"Hello. Here for scholarship paperwork signatures."
The TA sorting papers by the copier—looking like his soul had fled—turned at my greeting. A grad student TA crushed by chronic fatigue, dark circles drooping to his jawline.
"Ah... Name and student ID?"
"Third-year Kang Woojin."
"Kang Woojin... Ah."
The TA's hollow eyes suddenly sparked with life. He gawked like he'd found a legendary hidden treasure, flicking between my face and the monitor list.
"You're that legendary Kang Woojin? The guy who chugged booze non-stop in first and second year, racking up academic warnings, then swept first place in all five major required courses last semester—the insane grade turnaround freak?"
"Ah, yeah. Got lucky, I guess. Where do I sign?"
I just wanted to sign and bolt back to the library to calculate graphite gasket compression ratios.
"Here, this section. Hah, seriously jealous. Grades like that? Job offers on easy street later."
The TA handed over the papers with an envious sigh. I scrawled my signature in a flash.
"Thanks for your help."
I bowed and reached for the doorknob without a backward glance—right then.
Click.
The department chair's door inside creaked open, a deep voice flowing out.
"Kim TA. Did you say Kang Woojin just now?"
The TA's spine stiffened ramrod straight—I could see it clearly. The man emerging was a middle-aged guy with silver-rimmed glasses and sharp eyes.
Kang Woojin's memories blared an alarm in my head.
'Professor Park Tae-jun. Handles thermodynamics and solid mechanics. The pickiest, most notorious hardass department chair in mechanical engineering.'
Professor Park approached with hands behind his back. His gaze appraised me like a finely cut gem—or a predator eyeing plump prey.
"So you're Kang Woojin. Hard to catch a glimpse of you, but perfect timing."
"Ah, hello, Professor."
I bowed, instincts screaming bad vibes.
"Yes. That heat stress analysis report on pressure vessels you submitted last semester. Not undergrad level. You didn't just crunch equations—you nailed practical material limits and safety margins ready for real-world deployment."
"You're too kind. Just applied stuff from books. If that's all, I have to—"
"Busy? Heard rumors you're researching something in the library again. What's that notebook you're clutching?"
His eagle eyes zeroed in on my hugged notebook. No reason to hide it, nothing to snatch, so I answered flatly.
"Ah, personal interest. Designing alloy ratios for low-carbon steel enduring high heat and pressure, plus graphite gasket sealing structures."
At those words—
Professor Park's eyes behind the silver frames flashed brighter and fiercer than an exploding boiler.
"High heat and pressure... alloy steel and sealing structures?"
He swallowed hard. His specialty was thermal-fluid dynamics in extreme environments and new materials applications. No casual undergrad hobby topic.
"Woojin."
His voice turned syrupy soft and sticky. Nearby, Kim TA squeezed his eyes shut like hearing a death sentence.
"Any post-grad plans?"
"Pardon? Haven't thought about it."
"Don't say that."
He stepped closer, clapping a heavy hand on my shoulder. The pressure choked worse than when Valerius blockaded trade routes in Peluah.
"Come under me?"
"...Pardon?"
"Grad school. Integrated master's program—I’ll hook you up with full scholarship, personal lab spot, fat project funding for your alloy steel and pressure vessel research. Sound good?"
Grad school offer. To Korea's STEM undergrads, it was a devil's contract pawning your soul. Endless experiments day and night, infinite paper revisions, slavery to the prof.
"Can't let that shining talent rot. Join me to advance Korea's mechanical engineering a step?"
He dangled sweet bait like a sly merchant cornering you into stamping the contract.
If I were really Kang Woojin, the perks and prof's authority might've crushed me into a dazed "yes."
But.
My soul was Elpanso Carnoble—devourer of Peluah's textile markets, castle-builder atop shattered rules, grand merchant magnate.
'Trying to haggle a contract in front of a merchant? Please.'
Research funds? Scholarships? Buying my continental-richest soul and time with pocket change?
I gently but firmly shook off his hand, flashing a perfectly polite, business-grade smile.
"Truly honored by your generous offer, Professor."
"Right? Then lab starting next week—"
"But sorry."
I packed the notebook in my bag, driving the wedge home.
"I'm already prepping a personal business. Grad school's tiny lab can't contain the scale I'm handling."
"P-personal business? A third-year mechanical engineering undergrad doing what business...!"
"Oh, just remapping the continent."
I sauntered out, leaving stunned Park and the TA behind. From behind: "Kang Woojin! Think it over! I can sweeten the deal!"—the prof's desperate shout. I just waved lightly, never looking back.