Archive of Our Own ^beta

It’s late, and the library is empty.

This is your favorite time to be here. The quiet allows you to focus, to dive deep into the universes stacked all around you. You flip another page in the book in front of you. You’re lost to the world as you take in the diagram of a leatherback sea turtle’s esophageal papillae.

The intricate spikes of the lining fascinate you. They’re nature’s version of brutal efficiency, keeping jellyfish from harming the turtle and preventing them from slipping back out of its mouth. You trace a finger along the illustration, marveling at the alien beauty of it.

You almost don’t hear the soft creak of the floorboards behind you.

It’s subtle, like the sound a book might make sliding into place on a shelf. But it doesn’t come from the stacks; it comes from the direction behind your table. You pause. Not out of fear, exactly, but awareness. You’re alone. Or at least, you thought you were.

You close the book slowly and glance toward the reference desk. Mrs. Linden, the night librarian, always leaves at ten. You check the clock; it’s 10:19. There’s another sound, this time like fabric brushing against a bookshelf.

It had come from the aisle near the marine biology section. You stand slowly and step toward the source of the sound. Your sneakers squeak softly on the old linoleum, making you wince. You round the corner—and find no one.

You see nothing but the spines of aged books and the scent of paper and dust. You feel yourself relax—when a sudden CRASH from the history section startles you, causing you to whirl around on your heels. Your heart hammers against your ribs.

“Nice one, Raph! Real subtle. I specifically said, and I quote, ‘let’s be ninjas about this.’”

A low, gravelly rumble responds, full of indignant frustration. “Hey! I was being subtle! That cart-thing jumped out at me!”

“And you knocked over the display, too,” remarks a third voice.

The argument is so absurd that it overrides your fear. Curiosity gets the better of you, so you tiptoe to the opposite edge of the aisle and peer around the shelf—before your brain totally short-circuits as you take in the sight: four giant turtles, all bipedal, and they’re talking.

One, with a red mask, is rubbing his head while glaring at a toppled display of books. His shell is a fortress of spiked scutes. Another, in purple, is tapping impatiently at a device on his wrist, his brows furrowed in irritation. The one in blue, with dual swords strapped across his shell, leans against a shelf like this is all perfectly normal, while the one in orange squats next to a fallen book.

You don’t move, don’t breathe. You just stare.

Because it’s not just the talking or the towering presence of humanoid turtles in a library past closing time—it’s that you recognize them. Your mind races, flipping through years of field guides, documentaries, biology textbooks, and annotated sketches you’ve made in the margins. The details click into place, one by one.

You start with the one in red. He’s massive, broader than the others. His shell is jagged—sorta spiked—and thick as a bunker wall. His head is huge, his jaw built for crushing. Thick muscles cover his powerful limbs. The guy’s a Macrochelys temminckii—an alligator snapper.

Your eyes slide to the one in purple. He’s still scanning the room with his gauntlet, muttering about something. You follow the shape of his limbs: long, almost delicate. You look at his streamlined face, his snout. He has his shell covered by a device. Softshell turtle. Apalone spinifera or maybe ferox.

You’d have to see his shell to determine which.

Blue mask is standing just slightly apart from the others—relaxed, like this is all a game to him. But your trained eye notes the subtle tension in his stance, the readiness coiled behind his easy posture. You spot the distinctive crescent markings just behind his eyes, partially obscured by his bandana. His limbs are agile, his digits dexterous.

He’s a Trachemys scripta elegans—a red-eared slider.

And then there’s the one in orange. Because of the damaged display, he’s loading the books into the now-upturned cart. You follow the lines of his limbs—sturdy but not stocky—and catch sight of the dome-like curve of his carapace. Box turtle, you think with certainty. Terrapene carolina. Eastern box, maybe?

Your heartbeat slows—not from calm, but from a surreal awe. You’re seeing something impossible, something no book could have ever prepared you for. And yet, everything about them makes perfect sense.

You take a careful step back, but your shoe betrays you again—just a soft scuff this time. Still, it’s enough. Four heads snap toward you in unison. The red-masked one’s eyes narrow; his stance shifts protectively. The purple one lifts his wrist like he’s about to press something. Orange scrambles to his feet, clutching a book like a shield.

But it’s Blue who speaks first.

“Hey, hey, whoa—easy, guys.” His tone is calm but alert.

Red steps forward, trying to look intimidating. “You didn’t see nothin’, alright? Just … some very enthusiastic history buffs. Now turn around and forget this happened.”

You freeze, hands slightly raised in that universal “I come in peace” gesture. “I, uh …” Your voice comes out thin. “Actually, I think I did see something. Four turtle mutants. Of distinct Cheloniidae and Emydidae descent. One of which,” you glance at Purple, “is a softshell.”

Blue narrows his eyes. “Okay, either you’re incredibly weird or terrifyingly observant.”

You can’t help it; your academic instincts kick in full-force. “No, really. This is amazing. The variation in phenotype—look at the shell morphology! How do you even function bipedally with that center of gravity? And your vocal apparatus—oh! Do you breathe through cloacal respiration like some freshwater species or—”

A loud groan cuts you off.

“Donnie,” Red says, gesturing at you, “why is this person saying words that make my brain feel like it’s cramping?”

Purple—Donnie—doesn’t answer immediately. “Well, Raph,” he says dryly after a couple beats, “for once, we’ve encountered a civilian whose first reaction to discovering mutant ninja turtles isn’t to scream, faint, or run. No, they want to lecture us about cloacal breathing.” He smiles and gives a dramatic, pleased sigh. “My people have arrived.”

Raph scowls. “You would be excited.”

Orange steps forward, smile widening. “Whoa, you knew what we were? Like, not just ‘talking turtles’, but what species we are? That’s kinda baller.”

You hesitate, feeling all four of them still watching. “I, um … I specialize in herpetology. Reptiles, amphibians. Turtles are a particular focus.” You glance at Donnie again. “When I saw you, it all clicked.”

Donnie beams. “Finally, someone who speaks my language. You wouldn’t believe how many times I’ve tried to explain to Raph why his shell structure means he’s basically walking natural armor, and all he hears is—”

“—‘Blah blah, Donnie being a nerd again,’” Raph finishes. “Yeah, I know. Still don’t get why that’s supposed to matter in the middle of a fight.”

“It matters a lot, actually,” you say. Your nerves are still buzzing, but your excitement is winning out. “The jagged scutes on your carapace? They’re not just protective, they also break up your silhouette. It’s a form of disruptive camouflage—”

“Okay, cool,” Blue cuts in. “So, you’re not gonna scream or call animal control on us?”

You shake your head. “Absolutely not. If anything, I should thank you for not bolting when I started rambling about cloacal respiration.”

“Honestly,” Donnie says, “that’s a refreshing change of pace.”

Blue crosses his arms, a smirk playing on his lips. “So we’ve got a fan. A … very specific kind of fan.”

“Leo,” Raph grumbles, still looking at you with deep suspicion, “we don’t have time for this. We gotta find that book before—”

“Before what?” you ask, unable to help yourself.

All four turtles freeze, exchanging a look that communicates entire volumes of argument without a single word. Leo recovers first, his smirk returning, though it’s a bit strained now. “Before … the late fees get, you know, astronomical,” he says with a breezy wave of his hand. “This place is old school. I bet their fines are a real nightmare.”

You raise an eyebrow. “This is a reference library. The history section’s books are not available for checkout. There are no late fees.”

Donnie lets out a sharp laugh. “See, Leon? This is what happens when you try to improvise a lie in front of a subject matter expert. The narrative crumbles under basic peer review.”

“Okay, fine!” Leo throws his hands up in mock surrender. “You got us, Turtle-pedia. We’re on a top-secret mission, a race against time, a quest for a thingamajig of ultimate …” He trails off, looking to the others for help.

“We’re looking for a super old book,” Orange blurts out. “It has info about a mystic artifact that got swiped from a friend’s collection.”

“Mikey!” Raph hisses, his head swiveling to glare at him. “We don’t just tell random strangers our secret mission details!”

“They’re not random!” Mikey protests, gesturing at you. “They knew you were an alligator snapper! Nobody knows that!”

You can’t help but interject, your curiosity piqued. “He’s right. The pronounced supraoccipital crests are a dead giveaway. Most people wouldn’t recognize that. But a mystic artifact?” Your mind, usually grounded in hard science, stumbles for a moment. “As in … magic?”

“As in, capital ‘M’ Mystical, with all the problematic energy signatures and reality-bending headaches that implies,” Donnie confirms. “We believe a certain yokai is also after the book. We need to find it before he does.”

“Allow me to help,” you offer, a big grin splitting your face. “I know this place like the back of my hand.”

“I’m so glad we ran into you,” Donnie says, already pulling up a layout of the library on his gauntlet. “The catalog system here is practically ancient. Half of it’s not even digitized.”

Mikey looks at you, hopeful. “So, uh … you know where all the weird old magic-y history books might be hiding?”

You nod, already turning on your heel and beckoning them to follow. “There’s a restricted reference annex two floors down. It used to be a records archive for some secret society. They’ve got manuscripts back there that date to the early colonial period. Handwritten stuff. Most people don’t even know the sub-basement exists.”

Leo whistles low. “Dang. Okay, now I believe you’re a real fan of this place.”

As you lead them through the maze of shelves, you keep stealing glances at the turtles. Part of you still expects to wake up in a chair with your head in an open textbook, drooling. But no dream has ever had this many weird details.

When you finally stop at a narrow stairwell, Leo frowns. “Let me guess—rickety stairs that lead directly into the horror movie part of the library?”

You smile. “That’s the one.”

Raph sighs. “Of course it is.”

Donnie activates a small light from his gauntlet. You push open the heavy door at the bottom of the stairs and cold air whooshes out into the corridor. The floor is bare cement, and the lights are few and far between.

Donnie scans the room. “I’m detecting an energy fluctuation, southeast quadrant. Looks like someone beat us here.”

Mikey shivers. “I’m just gonna say it: if I see a haunted book that starts whispering Latin, I’m out.”

“Technically,” you murmur, “the library’s oldest volumes are mostly in Old Dutch and Latinized Algonquian.”

“Still out,” Mikey says quietly.

You weave between old oak shelves toward a caged section where they store anything considered too fragile or too weird for public browsing. As you reach the lock, Donnie’s gauntlet lets out a sharp ping.

“Uh-oh,” he mutters.

“Don’t like that sound,” Leo says, drawing his swords.

“Guys,” Donnie says, glancing at you, “we’ve got company. Cloaking field just shimmered. He’s here.”

A cold ripple tears through the air behind the nearest shelf. The lights flicker, and then a shape unfurls, like someone peeling themselves out of shadow. You stumble back instinctively. He’s tall—over seven feet, at least—and not human. Antlers sweep back from his skull-like face, and his body shimmers as though it’s only partly in this world.

“Too late,” the yokai hisses, its eyes locking onto the cage. “The tome belongs to me.”

Raph steps in front of you, solid as a tank.

“Whoa, someone missed the memo,” Leo quips as he joins Raph. “Halloween’s in October, Boney-Wan Kenobi.”

The yokai ignores the taunt. His form fully solidifies, revealing a tattered scholar’s robe over a body made of shadow. “You cannot comprehend what is at stake,” he says, pointing a long, skeletal finger. “That book contains a power that will undo the shackles of this mundane world.”

With a flick of his wrist, the shelves around you groan. Books fly from their resting places, soaring like guided missiles.

“Incoming!” Raph yells, planting his feet. He holds his ground as a barrage of encyclopedias and historical atlases slam into his shell. The impacts sound like boulders hitting a mountainside, but he doesn’t budge an inch.

You can’t help the thought that flashes through your mind, even amid the chaos: The interlocking scutes of an alligator snapper’s carapace are fused directly to the ribcage and spine, creating a single, incredibly dense structure. He’s not wearing armor; he IS armor.

“Show-off!” Leo calls, then zips forward. He doesn’t run; he slides, leaving a trail of blue energy. A portal rips open in the air right behind the yokai. Leo leaps through it, reappearing instantly to strike from the rear.

But his opponent is faster, dissolving into a swirl of ink, the katanas slicing through empty air. The yokai reforms a dozen feet away, near the caged section.

“His physical form is unstable!” Donnie shouts, before firing a volley of purple energy blasts that force the yokai to dematerialize again.

Mikey extends the chain of his nunchaku and swings it in a wide arc, intercepting a second wave of flying books and turning them into a cyclone. “Book-nado! Patent pending!”

You watch, mesmerized. It’s like seeing theoretical biology in motion. Raph is a living fortress, all power and defense. Donnie is the strategist, keeping his distance, utilizing tools. Much like a softshell turtle, which relies on speed and a painful bite rather than pure defense. Leo is agile; the speed and fluidity of sliders in both water and on land are well-known.

And he moves like water incarnate—graceful, impossible to pin down.

You barely register that you’ve moved, ducked behind a tall shelving unit as another blast of energy cracks against the cement wall where you’d been standing. The yokai begins chanting in a language you don’t recognize. The temperature drops another ten degrees.

And then there’s Mikey.

You peek around the corner again just in time to see him vault off a nearby stack, his weapon glowing with orange energy. His shell flashes in the flickering lights, each scute patterned like a hand-painted mandala. You catch a glimpse of his eyes: focused, alight with joy even in battle.

He swings his weapon, the glowing arcs intercepting the incoming book barrage. “Round two, baby!” he yells as he kicks off a shelf and somersaults toward the yokai.

The yokai screeches, recoiling from the strike.

“Keep him away from the book!” Donnie barks. “I’m almost done calibrating the containment seal!”

You spot the ancient tome slipping off the pedestal behind the creature. It’s going to fall. You act before thinking. “Raph!” you yell, pointing. “I’m going for the book!”

“Are you kidding me?!” he shouts back.

But you’re already diving, dodging between bookcases.

You reach the pedestal just as the tome starts sliding off. Heart hammering, you reach out and swipe it before it hits the ground.

Mikey lands next to you with a flip and grins. “Whoa, that was awesome!”

You can’t help the breathless laugh that escapes you as you clutch the heavy, leather-bound tome to your chest. The yokai screeches, and its form wavers as it sees its prize in your hands. “Give me that, human! That is not yours to keep!”

Tendrils whip out from the yokai’s body, aimed straight for you.

Before you can even flinch, Raph moves with a speed that defies his bulk, planting himself in front of you like a living shield. The tendrils lash against his shell but bounce off.

Alligator snappers can withstand immense pressure, your brain supplies, unhelpfully analytical. Their bite force is legendary, but their defensive shell structure is just as formidable.

The yokai, realizing it can’t get through Raph, changes tactics. The tendrils retract, and instead, black energy rushes around the massive snapper turtle, curving around Raph and heading toward you and Mikey.

“Containment field active!” Donnie’s voice rings out.

A brilliant purple light flashes—and where the yokai stands, a glowing, pixelated grid of energy hums quietly around him.

“Well,” Leo says, sheathing his swords, “that was a thing.” He winks at you. “See? Rickety stairs, horror movie section. Called it.”

Raph turns, his expression of fierce concentration melting into one of concern. “You okay?”

You nod, still trying to process what just happened. “I … I think so.”

“You were amazing!” Mikey says, giving you a friendly slap on the arm. “Total book-heist pro! We’re gonna have to give you a codename. How about Turtle-pedia?”

You manage a shaky laugh, looking down at the ancient book still clutched in your hands.

“And now we have the Codex,” Leo says, leaning over your shoulder to get a look. The cover is dark, worn leather with no title, only a spiraling symbol embossed in the center.

Donnie peers over Leo’s shoulder, adjusting his goggles with a hum of curiosity. “Huh. That symbol—it’s not just decorative. It’s a binding seal. And those etchings …” He scans the book with his gauntlet, watching as mystic glyphs glow under the device’s light. “Yeah. This book predates modern mysticism records by centuries. Possibly millennia.”

Raph lets out a low grunt of approval. “You were pretty brave, diving for that thing.”

“Thanks,” you breathe, your smile genuine and proud. “My fight-or-flight response defaults to ‘study the interesting thing up close,’ I guess.”

Leo claps you on the shoulder. “Alright, Turtle-pedia. You know our species, our secret mission, and apparently where this library keeps its haunted books.” He leans in, his expression turning serious. “So I’ve got one more question for you.”

You look at him, then at the others—at living, breathing impossibilities gathered in a dusty basement. “What is it?”

“You know any good all-night pizza places?”

You can’t help but laugh.