Colonel Hwang gave Sera two things on day eighteen: a request and a problem.
The request came first. Hwang arrived at B4 at 0730 — earlier than her usual 0800, which Sera had learned meant urgency that the colonel wouldn't openly display. She carried a tablet and a folder of physical documents, which in the military meant classified material too sensitive for digital storage.
"The Ability Enhancement Elixir," Hwang said. "How many vials do you have?"
"Five. One dose of fluid makes one vial. I used one for my own test."
"I need two."
Sera's hand stopped midway through pouring coffee. "For whom?"
"Two hunters. A-rank. They're leading a clearance operation on a B-rank dungeon in Busan that's been surging for three weeks. The dungeon boss has evolved — it's testing at low S-rank now. The team can't handle it with current capabilities."
"You want to juice your hunters with an S-rank enhancement potion so they can punch above their weight."
"I want to save twelve lives. The clearance team has twelve members. If the boss breaks containment, they die. If your potion works on combat abilities the way it worked on [Brew], we can prevent that."
Sera set the coffee down. "I tested it on myself once. One test. On a non-combat ability. I have no data on how it interacts with combat skills — enhancement abilities, physical augmentation, elemental control, none of it."
"You know it enhances [Brew] by a factor of ten."
"I know it nearly dissolved my cognitive function for forty seconds and left me unable to distinguish between reality and probability trees. That was a utility ability. Combat abilities are designed for destructive output. A tenfold increase in destructive output with unknown side effects could kill the user, the target, the twelve people you're trying to save, and a significant portion of downtown Busan."
Hwang set the tablet on the workbench. Sera saw the dungeon report — energy readings, clearance team roster, casualty projections. The numbers were bad. The dungeon boss had evolved twice in three weeks, an escalation pattern that suggested it would break containment within days.
"The alternative is sending S-rank hunters," Hwang said. "Korea has seven. Three are deployed internationally. Two are assigned to the DMZ gate. The remaining two are—"
"Let me guess. Unavailable."
"One is in surgery. The other refused the assignment." Hwang's jaw tightened. "S-rank hunters have the luxury of refusing."
Sera looked at the five vials of Ability Enhancement Elixir in their padded case. Each one represented a portion of the finite supply of black fluid she'd harvested from the Mugyeong gate. Each one was irreplaceable until she could either return to the gate or find an alternative source.
"I'll give you two," she said. "On conditions."
"Name them."
"First: I brief the hunters personally. I tell them what happened when I took the potion. I tell them about the cognitive effects, the sensory overload, the forty seconds of unresponsiveness. They make an informed decision."
"Agreed."
"Second: Dr. Kang monitors the test remotely. Full biometric telemetry. I want data on how the enhancement interacts with combat abilities."
"Agreed."
"Third: I get a second Mugyeong mission. Soon. Not 'after security review,' not 'when the committee approves.' Soon."
Hwang looked at her for three seconds. "Within the month."
"Two weeks."
"Three."
"Fine."
Sera pulled two vials from the case and handed them to the colonel. Three vials remaining. Two hundred milliliters of fluid. Fifteen potions' worth, minus the five vials she'd already brewed and the three she'd just given away.
Twelve potions' worth. Between her and the divine-class recipe.
The math was unforgiving.
---
The problem arrived an hour after Hwang left.
Sera had been working on her primary project — the hack, as she'd started calling it. A potion that could interact with [Brew] at the ability-code level and dissolve the System's modification. She'd spent three days since the enhancement test trying to develop the recipe, and she was failing.
The challenge was recursive: she needed [Brew] to design a potion that would change [Brew]. The ability couldn't modify itself any more than a program could rewrite its own compiler. Every recipe she attempted looped back to the same constraint — [Brew] could see the potion's potential, but it couldn't show her a recipe that included altering [Brew]'s own code, because the System's modification specifically prevented that calculation.
She was trying to pick a lock using the lock's own key, and the key had been reshaped to no longer fit.
The phone rang.
"Ms. Noh, this is the operations center. Colonel Hwang asked us to relay — two military personnel have been assigned to your lab as research assistants. They'll arrive this afternoon."
"I didn't request assistants."
"The assignment was initiated by Colonel Hwang's office. Security clearance has been processed. They'll report to you at 1400."
Sera hung up. Looked at Min-su. "Did you know about this?"
"No."
"She's planting people in my lab."
"Or giving you help."
"Those aren't mutually exclusive."
She spent the next three hours alternating between the hack and anxiety about the incoming assistants. Neither went well. The hack continued to resist her — every approach she tried hit the same recursive wall. And the idea of strangers in her lab, touching her equipment, breathing near her workbench, asking questions — it made her skin itch with a proprietary protectiveness that she recognized as irrational and felt powerless to control.
Her lab. Her potions. Her work.
She'd never shared a workspace before. Not in her apartment, not in her PhD program — she'd been assigned a shared lab at KAIST and had systematically driven out her lab partners through a combination of territorial behavior, hazardous experiments, and an unwillingness to label anything in handwriting that other humans could read.
At 1400, the elevator opened.
Two soldiers. Both young — mid-twenties, maybe. One male, one female. They wore the same black tactical uniform as Min-su but without the combat specialist's ease. Support staff. Lab technicians, maybe, with military training bolted on.
The man stepped forward. "Corporal Lee Tae-hyun, assigned to Brewing Division research support." He was tall, thin, with the restless energy of someone who fidgeted and had been trained not to. His fingers tapped against his thigh in a pattern Sera recognized — a person counting things they couldn't control.
The woman: "Corporal Shin Yuna. Same assignment." Shorter, broader, with a stillness that reminded Sera of Min-su but lacked his depth. This was a person who'd learned to stand still, not someone for whom stillness was native.
"Have either of you worked in a laboratory before?"
Lee: "I have a biochemistry degree from Seoul National."
Shin: "Hazardous materials handling certification. I worked the dungeon drop processing facility in Incheon for two years."
Biochem and hazmat. Not useless. Hwang had chosen carefully.
"Have either of you been briefed on what I do?"
Lee's finger-tapping accelerated. "We were told you create potions using unconventional methods and that some of your creations are classified."
"Unconventional methods. That's a nice way to say I blow things up regularly and the System sends me angry mail." Sera pointed at the workbench. "This is my primary workspace. Don't touch it. The cold storage contains ingredients, including several that are classified above your clearance and one that came from a gate that kills people. Don't touch those either."
"What should we touch?" Shin asked. No sarcasm — genuine curiosity.
"I'll tell you when I figure out what you're useful for. For now, familiarize yourselves with the lab layout, read the safety protocols I haven't written yet, and stay out of Min-su's corner."
They looked at the corner. Min-su was standing in it, watching them with an expression that communicated nothing and everything simultaneously.
"Is he always there?" Lee asked.
"He's my bodyguard. He's always where I am, which is always here, so yes."
Sera turned back to her workbench and tried to resume the hack. The assistants' presence buzzed at the edge of her concentration — new bodies in her space, new breathing patterns, new variables. She could hear Lee's finger-tapping. She could hear Shin opening cabinets, examining equipment, making the small sounds of someone learning a new environment.
Forty minutes later, she gave up on ignoring them and gave them work.
"Lee. I need a full chemical analysis of every ingredient in the stockpile. Composition, mana content, reactivity profile. Start with the dungeon drops and work through to the processed reagents."
"All of them?"
"There are approximately three hundred containers. You have the biochemistry training. Use the mass spectrometer — it's calibrated for mana-dense compounds but you'll need to adjust for samples above 90% purity."
"Shin. I need the cold storage reorganized. Group by mana reactivity, not by type. The current system is organized for military logistics — species, origin, processing date. I need it organized for alchemy — how strongly each ingredient interacts with [Brew]. I'll give you the reactivity readings."
"How do you measure reactivity?" Shin asked.
"I hold the ingredient and tell you a number."
"That's... subjective."
"It's the only measurement system that exists for [Brew]-specific reactivity. I'm the instrument. Get used to it."
They got to work. Sera watched them for five minutes, decided they were competent enough to not destroy anything immediately, and went back to the hack.
---
Day twenty. The hack wasn't working.
Sera had tried fourteen approaches. Each one hit the recursive constraint in a different way, but they all failed for the same reason: [Brew] couldn't design a potion that modified [Brew]. The System's lock was self-reinforcing — the very code that blocked the divine-class pathway also prevented any [Brew]-generated recipe from interacting with that code.
She sat on the lab floor at 3 AM, notebooks spread around her, and stared at the ceiling.
"I'm approaching this wrong," she said to Beaker, who'd climbed into her lap and was purring with the indifferent contentment of an animal that didn't understand failure.
The problem was framing. She'd been trying to use [Brew] to hack [Brew] — like asking a prisoner to design their own escape using only tools the prison provided. The tools were designed to prevent exactly that.
She needed an external tool. Something that wasn't [Brew]. Something that could interact with her ability from outside the System's framework.
She looked at the collection container.
The black fluid came from outside the System's taxonomy. The organisms in the Mugyeong gate weren't registered. The fluid's properties didn't match any known compound. When [Brew] processed the fluid, it produced recipes that strained the ability's classification system — S-rank results from a single ingredient, probability branches that terminated in the divine-class pathway.
What if she didn't need [Brew] to design the hack? What if she just needed to drink the fluid raw?
Not as a potion. Not processed through [Brew]'s recipe framework. Raw. Unmediated. The way the Gate 14-C survey team member had been changed — not by drinking a potion, but by exposure to the gate's environment until the gate's materials entered his biology directly.
The man had walked through walls afterward. His System status had been modified. New abilities. Unregistered skills. Whatever the Mugyeong fluid did to living tissue, it did it outside the System's control.
"That's insane," she said to the ceiling.
Beaker purred.
"I know. That's never stopped me before."
She stood up. Walked to the cold storage. Opened the container and looked at the black fluid.
Two hundred milliliters minus what she'd used for the Ability Enhancement Elixir. Maybe 180 milliliters remaining. If she drank a portion raw, she'd be consuming an unprocessed biological compound from an extradimensional organism, with no recipe, no probability reading, no [Brew] guidance, and no idea what it would do to her body.
She could die. The compound could be toxic. It could modify her biology in ways she couldn't reverse. It could change [Brew] in ways she hadn't predicted — for the worse, for the better, or for the incomprehensible.
She picked up the container.
And then she put it down.
Not because she was afraid — although she was, in the distant way she was afraid of all her experiments. But because she was a scientist, and scientists didn't drink unknown compounds at 3 AM without at least trying less suicidal approaches first.
She had assistants now. She had a lab. She had resources.
She went back to the workbench and wrote a new line in her notebook:
*Approach 15: Use the black fluid as a non-[Brew] catalyst. Don't route through the ability. Introduce it to the system directly — through biological interaction, not through alchemy.*
*But test it on something else first.*
*Something that isn't me.*
---
Lee found her in the morning, asleep at the workbench with her face pressed into a notebook. He'd brought coffee — real coffee, not the emergency-ration powder she'd been subsisting on. He set it at her elbow and retreated without waking her.
She woke to the smell, which was the kindest thing anyone had done for her in weeks.
"Where did you get real coffee?" she asked him.
"There's a break room on B2. I brought a French press from home." He hesitated. "I also brought filters. For the coffee, and for the mass spectrometer. The ones in the lab are degraded — they're passing particles they should be catching. I noticed during the analysis you assigned."
Sera looked at him. Lee Tae-hyun, biochemistry degree, nervous finger-tapper, coffee-bringer and filter-replacer. She revised her assessment of his usefulness upward by several notches.
"Show me what you've found in the analysis."
He'd been thorough. Two days of work, methodical and precise, cataloging the composition and mana content of every ingredient in the stockpile. His handwriting was legible. His data was organized. He'd even flagged anomalies — three containers whose contents didn't match their labels, two whose mana content was significantly higher than the registered grade suggested.
"These two," Sera said, pointing at the flagged high-mana containers. "What are they labeled?"
"Standard iron beetle carapace powder. Grade: commercial. But the mana content reads at military grade — 93% versus the expected 80%."
"Someone mislabeled them?"
"Or the beetles they came from were exposed to higher mana environments than the standard commercial dungeons. If these beetles were from a gate with elevated ambient mana—"
"They'd absorb more mana, producing a higher-grade carapace." Sera turned the container over in her hands. "Lee. Can you trace the supply chain? Find out which dungeon these came from?"
"I can try. The military purchasing records might have batch numbers."
"Do it. If there's a dungeon producing elevated-mana monster parts without being classified as high-grade, that's either a data error or a gate that's changing. Both are useful."
He left. Shin arrived shortly after — she'd been working the early shift, reorganizing the cold storage according to Sera's reactivity readings. She was efficient, systematic, and had the rare quality of asking questions only when she genuinely didn't understand something, rather than asking questions to appear engaged.
"I grouped everything into five tiers," Shin said, pulling up the new storage layout on a tablet. "Tier 1 is highest reactivity — your ambient mana crystals, the black fluid container, and the research-grade mana crystals. Tier 5 is lowest — basic monster parts, processed reagents, standard supplies."
"Good. Keep Tier 1 in the mana-shielded section. I learned the hard way that the ambient mana crystals contaminate nearby ingredients through passive field emission."
"You should probably tell the medics that. Corporal Lee's been working near the crystals for two days — he's had a headache since yesterday."
Sera stopped. "Where did he work?"
"At the secondary workstation. Four meters from the crystal case."
Four meters. Within the passive field's effective range. The mislabeled mana-shielded case — the one Sera had improvised from cold storage packaging — wasn't blocking the field as effectively as she'd assumed.
"Get him back here. Now."
---
Lee was fine. A mana saturation check showed mild elevation — 15% above baseline — that would normalize within a day. The headache was a symptom, not a danger. But the incident reminded Sera of two things: she was still making mistakes, and those mistakes now affected people who weren't her.
She stood in the lab that evening, after Lee and Shin had left for the night, and looked at the space she'd treated as hers alone for eighteen days. Two workstations now. Two new sets of equipment. Coffee filters that someone else had brought from home.
"They'll want to come back tomorrow," she said to Min-su.
He was in his corner. The corner that Shin had described as "always occupied" and Lee had described as "kind of intense."
"Probably," Min-su said.
"I don't want them to get hurt."
"People choose."
"Lee didn't choose to sit in a passive mana field for two days because I didn't properly shield the crystals."
Min-su looked at her. Five seconds. The longest he'd maintained eye contact since the Mugyeong extraction.
"You'd have sat there too."
He was right. She would have. She had, probably — eight days of unshielded exposure before she'd even identified the contamination risk. The difference was that she'd made that choice for herself, by herself, accepting the risk as part of the work. Lee hadn't had the information to make that choice.
She needed to be better about this. Not safer — she couldn't afford safe. But more honest about the dangers, so the people around her could decide for themselves how close to the fire they wanted to stand.
She wrote a safety protocol. Her first. Three pages of guidelines for working in a lab with mana-reactive materials, passive field emitters, and an alchemist who regularly created substances that didn't exist.
It wasn't good. It wasn't comprehensive. But it was a start.
She left it on Lee's workstation and went back to the hack.
Approach fifteen. The black fluid as a non-[Brew] catalyst. Direct biological interaction.
She needed a test subject.
Not herself. Not yet. Something else — alive, System-registered, small enough to monitor closely if it went wrong.
She needed a lab animal.
She picked up the phone.
"Supply office? I need a live specimen. Something small. System-registered, if possible — a dungeon organism, not a conventional animal."
"What kind of organism?"
"Something I can experiment on without anyone filing an ethics complaint."
The supply officer — the same one she'd called an infrastructure bottleneck two weeks ago — sighed with the particular exhaustion of a man who'd stopped being surprised by her requests.
"I'll see what we have."
She hung up and looked at the black fluid. Tomorrow, she'd start the real experiment. No more [Brew]-mediated approaches. No more trying to pick the lock with its own key.
Time to try a hammer.
