Busan was too beautiful to hide monsters.

Glassy skyline. Ocean breeze. Tourists snapping selfies on the boardwalk.

But tucked behind a fake logistics company near the industrial port sat Facility X13, a windowless, concrete block with no signage, no foot traffic, and no soul.

Do Rae and Do Rin stood across the street in maintenance uniforms, watching the building like wolves casing a butcher shop.

“I don’t like this,” Rin whispered. “Too quiet.”

Rae cracked her knuckles. “I love it.”

Entry was simple.

Swipe an employee ID Rin cloned from an intercepted Wi-Fi ping.
Walk through like you belong.
Smile like you’re underpaid and over it.

Inside: sterile corridors, soft LED lights, and people in lab coats who didn’t make eye contact.

The twins split up.

Rin headed for the security terminal.
Rae followed the signs for “Biometric Containment” — whatever that meant.

Rin’s override worked like a charm. One line of code, and every door on Level 3 opened.

She scanned for Subject Zero’s profile.

But what came up instead chilled her to the bone.

SUBJECT ZERO — STATUS: UPGRADED
CLEARANCE LEVEL: DIRECTOR ONLY
CURRENT LOCATION: ADMIN WING — FLOOR 1

“Wait… she’s not a prisoner?” Rin whispered. “She’s the freaking director?”

Meanwhile, Rae reached the containment sector.

No cells. No chains.

Just a glass-walled room at the end of the hall.

Inside stood a woman.

Mid-thirties. Graceful. Controlled. Hair in a tight braid. Expression unreadable.

She turned as Rae approached.

And smiled.

“You look just like Bong Soon at your age. Maybe a little meaner.”

Rae froze.

“You’re…”

“Yes. Subject Zero. Though I go by Yun Ji Woo now.
Welcome to the facility I built from the legacy that almost killed me.”

Flashback — 2003.

She was a test tube miracle. The first success. Not born strong, but made strong.

But the formula scrambled her brain. For years she couldn’t speak. Couldn’t think straight.

Until one day… she snapped out of it.

Not by accident.

By will.

She rebuilt herself. Slowly. Brutally. Secretly.

Then she made a deal with the very people who created her:

“I’ll fix what you broke. But you’ll give me power.”

Back in the present, Rae stepped into the room, fists tight.

“You’re behind this? The upgrades? The tracking? You’re using our DNA to build lab rats.”

“I’m building evolution,” Ji Woo said calmly. “You and your sister? You’re natural anomalies. I’m creating a world where anyone can be strong.”

“By injecting people with unstable formulas and watching them die?!”

Ji Woo didn’t blink.

“There’s no growth without sacrifice. You, of all people, should understand that.”

Just then, Rin’s voice crackled in Rae’s ear:

“Rae, you have to leave. Now. She’s not just a director—she’s not even fully human anymore. Her vitals are synthetic. She’s been augmented.”

Ji Woo heard it too.

She smiled.

“You shouldn’t have come alone.”

The lights snapped off.

Emergency red flooded the corridor.

Security alarms blared.

And from behind Ji Woo’s lab wall, something stirred.

Something big.

“Let’s see if you’re ready,” Ji Woo whispered.
“They say the twins are the prophecy.
Let’s find out if that’s myth… or marketing.”