The sealed door hissed open with a reluctant groan, hinges grinding after years of rust and disuse. The hallway beyond was pitch black — no lights, no sounds, just the heavy air of a forgotten place. Sarah clicked on her shoulder lamp and stepped inside, M590 shotgun braced, SHD brick flickering quietly on her wrist.
She moved slow, boots crunching lightly on dust and broken metal. Her HUD mapped each step as a blue wireframe overlay — outlines of old conduits, steam lines, and hollow ductwork. The brick pinged faint movement ahead.
Then: a sudden hiss and the whirr of a servo.
A ceiling-mounted Vault-Tec security turret jolted to life, its targeting motor stuttering as it failed to recognize Sarah's ID.
Vault-Tec Turret: "Access denied. Clearance not recognized. Targeting."
Sarah dove into cover just as it fired — three rounds sparking off the wall behind her.
She popped her SHD brick and released a short pulse burst. The sonar-like wave shorted the turret's motor, sending its aim spinning. A quick dash and a blast of buckshot from the M590 ended it in a hail of sparks.
Further in, another challenge — a rusted Protectron, lurching from its charging station with erratic steps and one arm sparking.
Protectron: "M-mainten...ance... error... eradic-ate...pest...s."
Sarah wasted no time — she primed her chem launcher, toggled to incendiary, and lobbed a capsule past it. A hiss — then WHOOMPH — the hall bathed in fire. The Protectron collapsed, legs melted.
Sarah (dryly): "Clearly not OSHA-approved."
[Deeper Into the Sublevel]
As she moved farther in, the air changed — more rot, more humidity. The floors sagged with decay.
Then the molerats came.
One burst from a ventilation shaft to her left — another from the wall itself, burrowing through cracked concrete. But Sarah was ready. Her sensor pulse lit the floor in glowing red markers, predicting burrow locations with pinpoint accuracy.
Three pinged.
She switched the chem launcher again — loaded a second incendiary vial — and fired just as the first molerat burst through.
Fire bloomed.
The molerats screeched as flames engulfed their tunnels. Buckshot followed, hammering the survivors as Sarah advanced with surgical precision. Every pulse swept the dark. Every flash lit rotting fur and bone.
What would've been a swarm became a slaughter.
Sarah: "so much for pest control."
But even as the flames died, her SHD brick pinged something deeper still — heat signatures, moving slowly beyond a locked bulkhead. Too organized to be molerats. Too clean.
Sarah (quietly): "You're not just hiding rats down here, Vault 81."
She reloaded, checked her launcher, and approached the next sealed door — its frame marked with cauterized claw marks and blackened fingerprints.
The bulkhead creaked open with a hydraulic groan, stale air washing over Sarah like the breath of a crypt. Her sensor pulse flared again—picking up a massive thermal signature—hotter than any molerat she'd seen. Her fingers tightened on the M590's grip.
The room ahead had once been a bio-research chamber: shattered glass tanks lined the walls, warning labels peeling, lights flickering amber. Scattered logs still glowed faintly on terminal screens—EXPOSURE TRIAL: SUBJECT RQ-01… GENOME STRESS REACTION DETECTED.
Then the tremor hit. A subtle quake through the floor.
Sarah: "Oh, hell... That's not normal."
From a ruptured pit at the far end of the room, she rose—nearly two meters tall at the hump, hide thick with iridescent lesions that pulsed like glowing boils. Her fangs were tusk-sized. One eye glowed amber. The other—a Vault-Tec injector needle embedded in the socket.
ISAC (alert tone): "Warning, Radiant Queen detected. Radiation saturation: 78%. Behavior profile: territorial. Aggression: MAXIMUM."
The Mole Rat Radiant Queen shrieked, a gurgling blend of sonic burst and chemical roar, then charged.
Sarah rolled left, slamming a flame chem round into her launcher and firing at the exposed gland cluster near the queen's neck. A hit—flames surged, but the creature plowed through, knocking over steel tables and sending a blast of acid-laced bile toward her cover.
Sarah (gritting her teeth): "This one spit?! What the hell!!!"
She ducked, pulse scanning for weak points—highlighting a ruptured tumor along the Queen's flank. Sarah pumped the M590—slug rounds now—and fired, the blast slamming into the mass and exploding it in a shower of black fluid.
The Queen shrieked, then burrowed—vanishing beneath the lab floor.
ISAC: "Warning. Subterranean movement detected."
The ground pulsed. Sarah jumped onto a fallen console, shotgun raised, just as the Radiant Queen burst from beneath, narrowly missing her. One claw gouged into Sarah's shoulder plate, ripping off a section of ceramic armor.
Sarah (snarling): "Alright, you overgrown Viral whack a mole—let's fucking dance."
Sarah blinds the Queen with a flash pulse Then Hits it with a triple chem combo: flame to glands, cryo to legs, and explosive to the jaw.
Lastly Sarah finishing it with a point-blank slug round to the eye socket, detonating the embedded injector.
The Queen staggers—then collapses, twitching violently as it irradiated core finally combusts.
Silence. Then smoke. Then stillness.
ISAC (calmly): "Target eliminated."
Sarah's boots crunched over shattered vials and melted steel as the last flames died around her. The Radiant Queen — a grotesque, irradiated molerat the size of a brahmin — lay still, twitching once before her collapsed form went still. Her tumors still hissed, oozing green-tinged blood.
A flicker on her SHD pulse caught Sarah's attention — a heat bloom deeper inside, behind a layer of bio-sealed shielding. Not hostile. Cool. Deliberate.
She followed the trail.
The Queen had been protecting something, not hunting. At the far end of the chamber, nestled between collapsed rebar and hardened nest resin, Sarah found it: a cloistered nest, lined with dozens of smaller molerat husks, babies, and a control door that had power — just barely.
Sarah torched the molerats kinks without pause. Incendiary chem bursts painted the chamber in fire, crackling and burning out the rot.
And behind it — a sealed medical door.
ISAC (faint tone): "Bio-lab secured. Status: Unknown occupant. Sub-Vault wing not listed in Vault 81 primary schematic."
Sarah activated the override panel. The door unsealed with a hiss of stale air and released a gentle chime.
From within floated a Ms. Nanny model robot, coated in years of dust but operational — eyes glowing a soft yellow in the room with chemical set and 3 locker makeshift casket.
Ms. Nanny Unit: "Oh! A visitor? How… surprising."
Sarah raised her shotgun slightly.
Sarah: "ID yourself."
The bot tilted in a practiced curtsy.
Ms. Nanny: "Curie. Scientific prototype unit C.U.R.I.E. I was assigned to Project Epsilon-81. This wing was sealed to contain the… unfortunate outbreak. I have remained in isolation for 83 years, 174 days."
Sarah's eyes narrowed.
Sarah: "You knew about these molerats."
Curie: "Oh Indeed. We believed we could extract regenerative properties from their genome. The Radiant strain was… unintended. Aggression levels grew too quickly. The nest was a byproduct of our failure."
Curie hovered toward a small, still-sealed cryo vault on the far wall.
Curie: "My final task was preservation. One vial remains — a universal serum synthesized from early-stage tissue. It may cure the boy above, though results are untested on post-War biology."
The vial rose from the cryo-locker, mist still clinging to the glass.
Sarah took it gently, pocketing it into a shock-proof case.
Sarah: "So only one vial remain. one unknown chance and no retry"
Curie floated beside her.
Curie: "If you return me to the surface, I will assist. I still hold the full medical data set and can continue research."
Sarah (quietly): "We'll need all the help we can get. I see"
She keyed her comms.
Sarah: "Vault 81 control, this is Sierra. The threat's neutralized. I have the cure. And I'm bringing a scientist."
Overseer McNamara (shaken): "I'm sorry...You're bringing what?"
Sarah: "A chance to save your people."