AUTHOR'S NOTE: Another prompt fill! I love trapped, panicked Cas so when I saw it, I had to write it. The prompt for this one was:

"A fave kink for me is Cas trapped somewhere, vulnerable and trying to hold out for rescue.

The bunker is now a safe haven for him, so when he's alone in it one time he finds the brothers have failed to warn him of an angel proof room. Until Cas walks in and the door shuts behind him.

The room is the stuff of angel nightmares( this is why the brothers said nothing). A medical table with restraints. Angel anatomy charts. Tools for breaking wings and siphoning Grace.

It triggers Cas and by the time the brothers come back Cas is a trembling bundle in a corner, wrapped in his threadbare wings.

Sam comforts Cas while Dean walls up the room."

"You sure you'll be okay alone for the night?" Sam asked, brow crinkling in worry as he hefted a duffel onto his shoulder.

"Sam, I have been alone in the bunker before," Castiel assured him. "You don't need my help with this hunt; you and Dean are more than capable of handling a ghost yourselves. If I need anything, I'll call."

Sam nodded though he still didn't seem completely okay with leaving Cas, and turned toward the entrance of the bunker just as Dean came down the hall from the direction of the garage.

"Car's all ready to go," he announced then nodded at the bag on Sam's shoulder. "That the last of it?"

Sam nodded. "Yeah, we're all set."

"Awesome, let's hit the road," he said with a clap and a grin. "We'll be back my morning, okay, Cas?"

Castiel nodded. "Good luck."

With a final goodbye and a wave from both brothers, they disappeared down the hall into the garage. After a moment, Castiel heard the sound of the Impala's engine starting up then the sound of the garage door opening and closing then silence.

He was alone.

Being alone didn't bother Castiel. The bunker was a safe place for him, a home he hadn't had in… ever. And now that he really thought about it, he usually only spent time here when the Winchesters were here and had only ever been in a handful of rooms: the common rooms like the library, map room, and kitchen; his bedroom (and Sam's when the hunter allowed him the use of his television and his Netflix); a few storage rooms; and the dungeon. But now, he'd be alone in the bunker all night.

He didn't require sleep so he couldn't pass eight or nine hours that way. He could eat but that would waste food when it wouldn't really give him any kind of nourishment and he wouldn't be able to taste anything but molecules anyway. And after the time he'd spent days at a time bingeing Netflix when he'd been too afraid to go outside, he wasn't sure he wanted to start that just yet. Maybe later in the evening if he had nothing else to do.

Maybe he should take this chance to organize some of the storage rooms, he wondered. He'd certainly know what more of the artifacts were than Sam or Dean – without having to waste time researching an item or, worse, accidentally triggering something terrible like casting a spell on themselves because they'd opened something they shouldn't have.

Yes, that sounded like a good idea. He'd learned somewhere that humans liked clean homes when they returned home from trips. The bunker was already virtually spotless so what better a surprise for the Winchesters than to organize a storeroom or two or three.

Decision made, Castiel made his way through the bunker where the store rooms were. The first two he came across were already neatly organized, the product of the Winchesters having spent a few years in the place with enough lazy afternoons with nothing better to do. But the third he found was full of boxes – both cardboard and wooden, the wooden ones containing sigils or seals – and nothing seemed to have any kind of organization.

The first few boxes were easy – books that he put on a table in the library to shelve later and a few scrolls with spells on them that he also took to the library to transcribe later so he could find somewhere to safely store the ancient scrolls, and a box of tools that Castiel pushed into the hallway to take to the garage later. When he opened up the third box, the first thing on top was a battered map. Upon closer inspection, he realized it was a map of the bunker, detailing all the rooms of the massive fortress.

There were even a few on the map that were marked with secret entrances and Castiel definitely had never seen any of those rooms before. He idly wondered if Sam and Dean had ever found any secret rooms.

Giving up on his organizing in favor of exploring, Castiel left the store room, pausing in the hall to pluck a flashlight from the box of tools (just in case) and to find his location on the map then trailed his finger across the page, taking note of the placement of each of the secret rooms. A room off the dungeon across the bunker caught his attention.

Why would a dungeon – a locked up room on its own – have a secret room attached to it?

Castiel decided that was going to be his first destination and pushed the map into the inside pocket of his trench coat as he crossed the bunker. When he entered the dungeon, he pulled the map out, using the image of where it attached to the dungeon to to find the physical entrance. He slowly moved across the room, lowering the map when he was sure he'd found it. As he skimmed his hand across the stone, he found a place where the stones didn't line up perfectly.

That had to be a secret door. The misaligned stones were too perfect.

Skimming around the seam, Castiel found a stone that pressed in slightly when his fingers added pressure to it. Experimentally, he pressed firmly then quickly stepped back when the wall opened right where the seam had been. The stones swung outward in a perfect arch, revealing a hidden, heavy metal door disguised behind a layer of stones. The musty stink of dust wafted toward him and Castiel wrinkled his nose, burying it into the crook of his elbow for a moment.

Tentatively, Castiel took a few steps into the darkened room. But as soon as he'd passed through the opening, three things happened at once: first, the door slammed back into place, taking the dungeon light with it and plunging Castiel into pitch black. Second, Castiel saw several sigils glowing grace blue as they activated. And third, he felt his grace being suppressed, locked away beyond his grasp, and a painful tugging at his back where his wings would meet his vessel if he'd chosen to make them corporeal.

The uncomfortable tugging quickly morphed into a sharp pain along the spaces where his wings would meet his vessel as if someone where cutting twin incisions in his back. He felt his grace acting without his consent, pushing his wings from the ethereal plane and forcing them into manifesting before it retreated back out of his reach. With an agonized cry, Castiel's wings – tattered as they were with clumps of feathers missing and others barely clinging to the wings' "arms" – flared out on either side of him.

Panting to catch his breath, Castiel tentatively reached back to feel where his wings had manifested, feeling them phasing right through his clothing. Well, at least whatever spell that had been hadn't ruined his favorite coat… He carefully flexed and moved his wings, noting that, after the initial discomfort, his wings worked just as they should with no ill-effects of the forced manifestation.

Now that the sigils had done their job, they no longer glowed, putting the room back into complete darkness. Castiel scrambled to flick on the flashlight he'd found, slowly panning it around the room to get his bearings and noticing that everything was caked in layers of dust which explained the unpleasant smell. He wanted to find those sigils again to get a closer look so he could learn why his wings had been forcefully brought out and he needed to find an exit.

Castiel wasn't sure what to think of the room as the rest was revealed to him.

The stone walls were covered in Ennochian sigils, every available space being used to place sigils of varying sizes. It reminded Castiel of the barn he'd first met Dean and Bobby in when they'd summoned him. Even the ceiling was painted in sigils except the very center where a lone, uncovered light bulb hung.

He easily found the ones that had been activated as soon as he'd stepped into the room. They were positioned in a small cluster, meant to work together for a common result: in this case, it had been forcing an angel's wings to become visible. One of them was meant to act as an "ignition" of sorts, activating as soon as an angel passed through the doorway to the room. That explained why Castiel had no control over his wings' visibility as soon as he'd crossed the threshold.

Castiel moved to try to pull the chain attached to the light bulb to illuminate the entire room at once. As he panned his flashlight in that direction to light a path for himself, he noticed that three tables were set up under the light, slightly off center beside a drain in the floor. Two of the tables had been placed perpendicular to the center one, creating a T. Curious, Castiel carefully stepped under the light and pulled the chain to get a better look.

The tables were stainless steel, restraints welded into all four corners of the center one. A set of stirrups were folded against the end of the center table to be out of the way of the ankle restraints and could be set upright when in use. Castiel didn't want to think about what reasons those would be used for. The restraints on the other two tables were placed in the center at the ends closest to the middle table and to the top of the table at the other end. Castiel suspected those were to hold down an angel's wings.

Beside the table, a rolling cart was set up, tools meticulously laid out over a small segment of sterile tarp. When he peered closer at them, he noticed a syringe very similar to the one that he and Sam had used to pull the last of Gadreel's grace from the hunter along with several pairs of scissors, tweezers, and scalpes in varying sizes. On the next shelf down, medical tape, gauze, antiseptics, and ointments were all organized in the small space. The very bottom shelf of the cart held boxes of rubber gloves and plastic aprons, a suturing kit, and a few rolls of duct tape.

Castiel swallowed hard, slowly backing away from the horrifying setup. He didn't want to think about what kinds of torture to angels (because the sigils around the walls clearly meant this room was angel-specific) could be or likely had been done.

Two shelving units had been set up along the wall closest to the table. One held towels and cleaning supplies. The other contained larger tools that weren't usually used in a medical setting, even a pseudo one like this room. Castiel recognized some of them as things Dean would use in the garage. Various sized mallets hung from hooks along the very bottom and above that, the shelf was lined with boxes labeled "clamps," "screwdrivers," and "hammers."

Turning away from the other tools because Castiel shuddered to think what kinds of horror could be caused by using those kinds of tools on a body, the angel noticed a sink against another wall. Several large metal buckets were stacked on one side. On the other, three bins were lined up beside each other, all with lids and labels: hazardous waste, recycling, trash.

As Castiel turned to search near the door for another way to open it to get back out, he spotted several posted lining one wall over the sigils. He was going to ignore them in favor of finding a way out of this unsettling place but an image on the one in the center caught his attention. Reluctantly, he slowly crossed the room to peer closer at them.

They weren't the same kind of material as normal posters. These seemed more like large segments of parchment paper that someone had hand-drawn diagrams on then taped to the wall. Markings had been added in different colors. As Castiel peered at the one that caught his attention, horror washed over him as he realized it was the anatomy of an angel's wing. A left wing, Castiel noted though one would only need to know the anatomy of one to figure out the other as wings tended to be symmetrical. Someone had added a note in red marker near the top joint of the wing which had been circled.

Can be broken by hand.

Further down, closer to where the wing would meet the angel's vessel, another note had been added under the entire bone segment.

This bone is stronger. Requires large mallet. Cannot be broken with pressure from clamps like the bones of the vessel.

Castiel swallowed around the bile in his throat. These notes clearly meant someone – probably older Men of Letters – had experimented on an angel, tested its wings' durability, had actively put an angel through severe pain for what Castiel assumed was the sake of research.

One of the other posters seemed to be a close-up of where the wing met the angel's vessel. Notes had been added here, too.

When an angel's wings are visible, they meld seamlessly with the vessel's flesh. Upon surgical exploration, it was discovered that the bone of the wing does not surpass the exterior flesh. No muscle in the vessel's back connects to the wing from the inside. All attachment is exterior. Further surgical exploration revealed that the wings can be removed surgically just like any human limb.

Castiel pressed a shaking hand to his mouth and nearly dropped the flashlight out of the other. If he understood this note correctly, then… they had removed an angel's wings! Forced them onto the corporeal plane then taken it away with no ability for the angel to ever get it back! They'd taken an angel's ability to fly!

Castiel wrapped his tattered wings around himself and shuddered, his free hand pushing into a clump of feathers and grasping the primaries protectively. He knew what it felt like not be able to fly. His wings were too bare and weak to sustain him in flight but he knew he could someday when they'd healed fully. But to know that he could never again take flight?

Just the thought of losing that freedom made his heart break for the angel that it had actually been done to.

Movements more desperate than before, Castiel hurried back to the door. This side didn't blend into the wall around it like the outside but it was completely smooth and covered in sigils just like the surrounding walls. There was no handle and desperately feeling along the walls on either side of it didn't produce any kind of trigger to open it like on the other side. Hoping he still had his angelic strength even if his grace was out of his reach, Castiel placed his hands firmly against the metal and shoved but the door didn't budge. He tried several times but it seemed his grace had been locked too far away, rendering him the equivalent of human.

Then he remembered his promise to call Sam if he needed them and frantically searched his pockets for his phone. After two passes through the pockets in the coat and suit jacket and the suit pants, Castiel remembered that he'd left his phone charging in the library. He'd checked it periodically when carrying things back and forth just in case Sam and Dean had needed him.

With the realization that he had no way of calling anyone for help, Castiel came to a horrifying conclusion: he was well and truly stuck in this room.

Uneasy around the set up in the center of the room, Castiel scurried into a corner far away from the table and the tools. He tucked himself into the corner with his knees to his chest and brought his wings around himself, creating as much of a cocoon as he could.

With no way to escape and nothing to occupy his mind now, Castiel couldn't stop imagining the horrible things that must have happened on that table. One of his brothers or sisters, tied down with their wings forcefully spread out on either side of them. He imagined a Man of Letters using an angel blade to dissect the wing for their sick diagrams, blood trickling down the table onto the floor beneath and into the drain while his sibling screamed loud enough for their true voice to bleed through their vessel's voice.

Castiel's own wings ached with imagined pain and he stroked his hands down the arms of his wings to chase away the phantom pains. He swallowed back the urge to vomit as he remembered the note on one of the posters: the wings can be removed surgically just like any human limb. Morbidly, he wondered what they had done with the angel's wings once they'd taken them? He made a note to search the store rooms thoroughly for angel feathers, positive the old Men of Letters would have stored them for spells. Once he got out.

Because he would get out. Sam and Dean would return from their hunt and they'd look for him. They knew he wasn't planning on leaving the bunker and they'd see his phone in the library and they'd know he was here somewhere.

But he was in a secret room. With the map to find said secret room in his coat pocket. And he had no idea if they even knew the bunker had secret rooms. How long would they search for him before they realized he wasn't in the main parts of the bunker? And once they did, they'd probably try searching outside of it for him, assuming someone had kidnapped him.

They'd never find him.

Castiel felt chilled as dread settled like a rock in the pit of his stomach. Spending forever locked in here because no one knew this room existed, living for an eternity because angels couldn't grow old and die or starve to death. Or worse, the pain of actually starving to death because his grace was out of his reach and probably not sustaining his vessel.

Castiel hoped he wasn't locked in here long enough to find out which scenario was true.

In an attempt to block out his surroundings and calm himself, Castiel wrapped his wings as snugly around himself as he could and closed his eyes, breathing deeply and letting himself fall into a meditative state. It was the closest, as an angel, he could get to sleeping and he welcomed the chance to get out of that room. Even if it was only in his mind.

But it didn't quite work the same without his grace. So close to human, attempting a meditative state turned out to be the human equivalent of daydreaming. And when Castiel's mind wandered, it inevitably returned to the frightening thoughts and imaginings of what could have happened in this room. Except this time, the form of a faceless brother or sister on the table was replaced with himself. And the faceless Man or Men of Letters became Sam and Dean.

They'd force him onto the table, tie up his wrists and ankles. He'd try to use his wings to beat them away but his wings were too damaged that the brothers would easily overpower them and tie those down, too. They'd cut away his clothes and one of them – in Castiel's horrifying imagination, it was Dean – would pick up his angel blade and they'd discuss where to start dissecting him, ignoring his pleas and cries to let him go, please!

Castiel keened as he forced himself back into reality, actually welcoming his surroundings because at least in reality, the room was empty save for himself. His wings trembled around him and then Castiel realized his whole body was shaking.

"It wasn't real," he mumbled to himself, trying to stop the tremors running down his spine. "They wouldn't do that. They'll save me. They'll get me out of here."

Deciding that trying to meditate – or sleep, for that matter – wasn't a good idea, Castiel forced himself to stay awake. Even as time slowly dragged on and he felt his eyelids growing heavy, his vessel demanding sleep without his grace to keep it running. He'd feel his eyes slide closed and his head tip forward before he jerked it back upright and snapped his eyes wide open.

Similarly, as time went on and his vessel went longer and longer without his grace sustaining it, Castiel soon felt the uncomfortable pangs of deep hunger knotting up his stomach. He grimaced and pressed his palms into his abdomen in an attempt to relieve the ache. Thinking back, he tried to remember the last time his vessel had actually gotten proper food. He'd eaten a number of times when he'd been human and had attempted a sandwich when he'd become an angel again but had abandoned it after one bite when all he could taste was molecules.

As his stomach growled and the ache intensified, Castiel curled in on himself with a groan of discomfort. He almost wondered if the nightmares were worth going to sleep to pass the time and to get away from the ache. After a while, the choice was taken away from him. He couldn't fight the heaviness in his eyes and it became harder and harder to keep them open.

Castiel struggled against the hands grasping roughly at his upper arms, two sets squeezing each upper arm like a vice. Normally, he could easily overpower any human but this room… this room locked away his grace, sapping his angelic strength. He tried beating his wings against his captors but they were in bad shape and he couldn't muster the strength necessary to free himself.

"Let me go!" he pleaded as he was held down and strapped to the tables, his wings being forced to stretch out so they could be restrained.

"I gotta say," one of them said and cold dread washed down Castiel's spine as he recognized that voice. "Cas, your wings are hideous. Not as 'angelic' as I'd imagined."

Then he stepped into the light and Castiel felt sick with horror as Dean leaned into his line of sight, backlit by the harsh light above the tables. And if Dean was one of his captors… Castiel turned to his other side to find Sam standing over him, studying the wing closest to him.

"Why are you doing this?" Castiel whispered. "I thought you were my family…"

Sam snorted and the smile that curled his lips held none of the warmth Castiel was familiar with; it was cold and mocking. "You really think we thought you were family?"

"Sammy here's been itchin' to really study an angel," Dean said. "Nerd that he is. He really wants to get up in there, see what makes you tick, makes you break, makes you scream."

"And how can we pass up the chance to stock up on spell supplies?" Sam asked rhetorically as he plucked one of Castiel's few remaining primary feathers, making the angel grunt against the pain and his wing twitch as much as it could while restrained.

"Angel feathers are rare, you know," Dean added, holding a wooden box etched with Ennochian sigils for Sam to collect the feathers as he continued to pluck them.

"Stop," Castiel moaned, struggling as much as he could. He didn't have many feathers left and they were going to take every last one! Dean was right – his wings were hideous. And they were going to look even more grotesque when bare.

His pleas and struggles did little to deter the brothers from their malicious fun and soon, Castiel's wings were bare, every feather he had left sealed into the box.

"Grace next?" Dean asked.

Sam nodded and Dean handed him a thick syringe with a terrifyingly large needle. Castiel quickly shook his head in protest, trying to wiggle as close to Dean's side of the table as he could but he knew he couldn't escape what Sam had planned.

"Remember when you used this one me to pull out Gadreel's grace?" Sam asked bitterly. "Shoving the needle so far into my neck that I thought I'd die from the pain? Remember how you stopped short of killing me?" He didn't wait for Castiel to answer. "Yeah, I'm not gonna be that nice."

Dean held his head still while Sam pushed the needle into his neck as far as it would go, both of them ignoring Castiel's cries of pain and his weak thrashing. He could feel his body weakening as Sam extracted his locked grace. His pleas for them to stop turned into incoherent babbling the longer the brothers ignored him.

Once the grace was fully extracted, Sam passed the needle back to Dean who gently laid it back in its case and closed the lid. "He's basically a human now," he mused. "A human with hideous protrusions coming out of his back."

Sam nodded thoughtfully as he studied what was left of Castiel's wings. "He's never going to fly again anyway," he added thoughtfully.

Dean hummed an agreement, peering closely at the wing closest to himself. "Surgery?" he asked.

"Yeah, sounds good," Sam agreed.

Castiel struggled harder, knowing exactly what they intended to do but his body was weak without his grace sustaining it. His struggles as they released the restraints and flipped him over did little to even slow them down. Then he was on his front, back in the restraints with his head turned to one side to keep from smothering against the unforgiving metal table.

"Please, don't!" he pleaded as he felt Dean take hold the wing closest to Sam, holding it steady for his brother. Castiel tried to beat what was left of his wings against the brothers but then they both took hold of a wing one either side of the top joint then snapped.

Castiel screamed in pain as both wings were broken at once, feeling sweat beading on his face and his stomach roll with nausea at the pain. When the Winchesters let go, Castiel realized he could no longer move his wings to fight against them. He was powerless to stop Dean from holding one wing steady while the sharp sting of a scalpel was slowly worked into the base of his wing where it met his vessel.

He screamed at the pain until his throat was raw and his voice came out rougher than normal.

"Cas!"

"Stop," he moaned, a sob escaping him as tears pooled in his eyes.

"Cas!"

"Please," he whispered around another sob. "Let me go."

"Cas!"

Castiel's eyes snapped open to find green eyes too close for comfort, his mangled wings the only barrier between himself and Dean. No! They were going to take his grace and his feathers and his wings! When Dean reached out to him, Castiel snapped his wings out toward him in defense as much as he could move in the corner he'd tucked himself in. He felt his body shaking violently with fear and he snarled, flaring his wings out threateningly.

"Whoa, easy," Dean soothed from where he'd landed on his ass, hands held up in a placating gesture. "Cas, it's just us."

"You can't have my feathers!" Castiel yelled at them, snapping his wings in warning. "Or my grace!"

From behind Dean, Sam tilted his head in confusion. "Cas, we're not going to take your feathers or your grace," he said calmly. "We just… We couldn't find you anywhere in the bunker and I remembered finding this room awhile ago and I had this sinking feeling…"

Castiel blinked in confusion as Sam's words sunk in. They found him here? They hadn't put him…

He remembered!

He'd been organizing and the map and the secret room… This was his Sam and Dean! Not the twisted versions of his nightmare!

With a relieved sob, he threw himself at Dean, still trembling but more so from relief now. He clung to Dean as the elder Winchester's arms wound snugly around his waist.

"I got you, Cas," he soothed, rubbing a hand soothingly up and down the angel's spine.

"Out," Castiel sobbed. "Get me out."

Dean nodded and lifted him as he stood. Castiel's knees were weak and his head spun as they stood so he clamped a hand down onto Dean's shoulder. Sam immediately came to his other side and helped support him as they exited the room.

As soon as he was back into the dungeon and out of the room heavily marked in sigils, Castiel felt his grace reawakening and filling his vessel. The aches of hunger bled away and he felt the remnants of exhaustion melt away. He put his wings away and eased his grip on the brothers.

"I don't ever want to see that room ever again," he growled, standing on his own now that he felt strong again. "Why didn't you seal it up as soon as you found it?"

"I meant to," Dean said sheepishly, rubbing at the back of his neck. "But then cases happened and… I forgot. I never thought you'd ever find it but I should have known having a room warded so heavily against you wasn't safe."

"Cas," Sam added, "we're so sorry."

"I'll get that room sealed up and you'll never see it again," Dean assured.

A few days later, Dean was making good on that promise. He'd gone to several different hardware stores and purchased as much stone as he could that resembled the stone around the dungeon and all the other necessities required for putting up a wall. He'd removed the door and they'd decided they were going to just shove it into the room and seal it away. While he worked at filling in the hole left by the door, Sam and Castiel stood back to watch, Castiel needing to watch, to see that horrible place sealed off for good, and Sam watching Castiel to be sure the angel was holding up okay.

It was a slow process and the longer Castiel stood there, able to see inside the room, his memories of his nightmare in that room kept coming back and he had to remind himself that it wasn't real. Sam and Dean would never have done that to him and he could feel his grace thrumming through him, perfectly intact.

He gasped and flinched when he felt an arm come around his shoulders but relaxed when he realized it was just Sam drawing him into his arms. The angel melted into the hug and buried his face in Sam's shoulder. He didn't realize he was trembling until Sam started running a hand up and down his back.

"It's okay, Cas," he soothed. "We don't have to watch this, you know. We can let Dean deal with it and go do something else until he's done."

"No, I'm alright," Castiel assured. "I need to see this finished."

Sam nodded and tucked Castiel close.

Held in a soothing embrace, Castiel found it easier to watch Dean. Instead of focusing on the room behind the wall slowly taking shape, he instead focused on what Dean was doing, quickly picking up on the pattern it took to lay each stone of the wall. Before he knew it, Dean was putting the last stone in place and stepping back.

"Okay," he said on a weary sigh. "Just need to let it set."

"Thank you," Castiel murmured from his place against Sam's chest. "Both of you. I truly appreciate the work you've gone through just because I was afraid."

"You're family, Cas," Dean said as he came to join them, wrapping his arms around Castiel and Sam from one side, effectively cocooning the angel between the two of them. "We care about you, man. If it scared you that badly, no way am I gonna dismiss your fears just because soothing them requires some hard work."

Sam nodded in agreement, squeezing the angel tighter, and Castiel sighed, feeling himself fully relax for the first time since he'd first set foot in that room and felt the sigils forcing reactions out of him. He'd be okay now. The Winchesters would make sure of that.

Though Castiel knew it would be a long time before he'd be comfortable beign left alone in the bunker again after this.