A/N - I don't know how often I'll have time to update this, but it's already entirely written so it'll definitely end up complete. Very Minor spoilers for season thirteen

"I have an idea," Gabe announced, waltzing into the bunker's kitchen. Sam looked up at him, eyes narrowed, and on the other side of the table he saw Dean do the same.

"What sort of idea?" Sam asked suspiciously. If he had learned one thing from the various interactions he'd had with Gabriel over the years, it was that his ideas could be good or they could be very, very bad. Sam couldn't get even the barest hint of where this might be going from just the archangel's tone of voice.

Sam supposed he should be glad that Gabriel was even talking to them, let alone coming up with strange, grand ideas. It hadn't been all that long ago that Gabriel had been a near-catatonic mute, and his recovery had been coming along strikingly well. But still, that didn't mean Sam wanted Gabriel...selling sex toys out of the bunker, or trying to make a mockumentary about Cas, or making all the furniture edible, or anything else along those lines. He thought he was fully justified feeling a bit wary of Gabriel and his ideas.

"No, this is a good one," Gabriel said, his tone of voice still leaving Sam anxious. "This one benefits you guys, I promise."

"Is it to teach us a lesson?" Dean asked. He was nervous enough that he had set the burger he'd been eating down on the plate.

"No, it's a real...you know I'm practically a god, maybe you should respect my ideas more, it's...nevermind. It's a way to recharge my grace, actually. Which last I checked is something you need."

"Alright," Sam said, still a little skeptical but more excited now that he knew this plan was not intended to be any sort of practical joke.

"It's kind of dangerous," Gabriel said.

"So's everything in our lives," Dean said. "Spit it out."

"Well, at one point in time, I had access to this special plant that recharges angel grace," Gabriel said. "But I...don't have access to it anymore."

"I like time travel," Dean said, and he was clearly into the idea enough that he had picked his burger back up. "Where are we headed? Wild West again?"

Sam tried to ignore how hopeful Dean looked at the idea of that. But it was kind of sweet.

Gabriel shook his head. "Farther back."

Dean's eyes widened. "Medieval?"

"Nope. Farther."

"Romans!"

"Nope."

"Dinosaurs?" Sam asked with a small chuckle. He was joking - he knew there was no way Gabriel would send them back that far.

But to his shock and horror, Gabriel nodded.

"Yep," he said. "Jurassic. 150 million years ago."

Dean's eyes popped so far open that Sam thought they might fall out of his head. "DINOSAURS? JURASSIC PARK? FOR REAL?"

"Hell yeah," Gabriel said with a smirk. "Go pack for Utah in the Jurassic. Deserts, rivers, conifer trees...big lizards. Oh, and find my little bro, tell him what's going on."

Dean was gone before Gabriel could finish the sentence. Sam sighed and followed, unable to shake the feeling that this trip was going to be even more disastrous than the fate of Jurassic Park.

One hour later, on the dot, Dean was standing in the entrance of the bunker with his baggage. Cas trailed in behind him, looking slightly wary, as though he expected Gabriel to jump out with a nasty surprise. Dean couldn't exactly blame him, not after the "snakes-in-your-face" incident that Gabriel had insisted would go viral.

"I got you a hat," Dean said as Cas peered around at all the doorways. The angel turned back to him, raising an eyebrow.

"Is it like the one you're wearing?" Cas asked skeptically.

Dean grinned. He'd managed to find a collection of vintage Indiana Jones-style hats in one of the back rooms, along with some photos of Men of Letters wearing them in a faraway jungle. This is what he'd spent the better part of the hour doing.

"Yeah," he said proudly, producing it. "I have one for Sam, too." Dean considered the angel, who was taking too long to voice his excitement. Without waiting for permission, Dean put the hat on Cas's head.

"Do I have to-"

"Yes," Dean answered firmly.

"Nice hat, Dean," Sam said from a nearby doorway, stepping into the room. Dean chose to ignore any possible sarcasm in the statement and threw a third hat to his brother.

"Got you one too."

"Goody."

Sam held the hat in his hands, looking a little annoyed but doing a good job of hiding it. Cas, seeing from Sam that he had at least some recourse for getting the hat off of his head, removed it and set it on the steps. Dean frowned in disappointment.

It took only another minute or so for Gabriel to emerge from the bunker. "A few last things," he said. "First off, you guys have two days. No more, no less. Nothing I can do about that. Second off, I'm going to be needing some of my main dude's energy for the spell."

"What?" Cas spluttered. He held up his hands, like he could physically ward off Gabriel coming at him and stealing his grace. He looked at Dean with wide, anxious eyes.

"Sorry," Gabriel said, shrugging. "Couldn't make it work any other way. No one knows better than you three exactly how much grace I have, and you must know it's not enough. Not for sending three passengers back 150 million years. Can't do it without you, bro."

"Fine, fine," Cas said, but he didn't look happy about it.

"Are you ready?" Gabriel asked.

"Um, yeah," Dean said, speaking for the other two. "Let's see some dinos."

He had a split second to register Gabriel reaching towards his forehead with two fingers, and then everything went black.

Dean woke up when the breath was knocked out of him. He took the briefest moment to collect himself, then opened his eyes.

The light looked...different. That was the first thing he noticed. Somewhere in the back of his mind he registered that it might be because the atmosphere was cleaner, or perhaps because there was no artificial light to muddy the glow that came from the sun. But that didn't matter. What mattered was that it was quite clear right away that Gabriel had...done it. They were in the Jurassic period. Or at least, it was very clear they weren't in twenty-first century Kansas anymore.

"Did it work?" Sam asked from somewhere to his right.

"I...I think so," Dean said, pushing himself into a sitting position with a slight groan. He didn't think he was injured at all, but he felt rather sore and worn out from his journey through time.

Dean turned his head towards Sam, who was also struggling to get himself up. He reassured himself that his brother seemed no worse for the wear, then looked around in confusion.

"Sam...where's Cas?"

Sam shook his head, beginning to look around for the angel.

"Cas!" Dean raised his voice, not wanting to shout too loudly and attract any dinosaurs. He took a second to appreciate that he'd just considered dinosaurs as a serious problem and continued searching for his friend. "Cas!"

There was a loud splashing from the river and a bedraggled head poked out of the water, spluttering.

"You okay?" Dean said, trying not to chuckle at the angel's miserable expression.

Cas stood up, water streaming from his clothes, and began making his way unsteadily to the bank. Luckily, the water only seemed to reach to about his knees.

"I'm fine," he said, a little angrily, reaching the bank and climbing out of the water. "Let's go as far as we can tonight."

"Spell didn't take too much out of you?" Dean asked, eyeing his friend with worry. Cas looked a little too pale for his liking.

"I'll be alright," Cas said impatiently. Dean shrugged, then glanced up to the treeline, looking for dinosaurs.

"This is the best trip ever," he muttered to Sam, then set off after the waterlogged angel.

Cas didn't want to admit it, but he was beginning to think that Gabriel's spell had drained him more than he'd initially thought. It hadn't been so bad at first, he'd just felt a little unsteady on his feet. But now, after walking for only a few minutes, he was feeling out of breath and dizzy. He wasn't supposed to feel like that.

And even without considering how weak he felt, he was cold. The river water had been icy, and Cas had landed in it so suddenly he hadn't been able to keep his footing. If you asked him, Gabriel had probably done it on purpose. The archangel enjoyed "teasing" him.

Cas glanced up ahead at the Winchesters. Dean had grabbed Sam's shoulder and was pointing excitedly at the horizon, where a scaly head was visible. Cas sighed. Dean didn't torment his younger brother….

Cas shivered, realizing that he was lagging behind, but unable to go faster. His legs were just so cold, and everything felt numb, and he was starting to shiver. All he really wanted to do was curl up in a ball on the ground and wait until he felt warm again.

"Cas?" Up ahead, Dean had turned around, and he and Sam were coming back towards him. Cas considered meeting them halfway, but after giving the matter a little consideration, he opted for just standing there and trembling.

"Hey, buddy, you sure you're okay?" Dean asked, sounding concerned.

Cas nodded mutely, balling his shivering hands up in the wet sleeves of his jacket.

"Hey, we can stop here if you want, this is probably as good a place as any, and we can make a fire to get you warm-" Sam started.

"No," Cas said firmly. He pointed to the middle distance, where there was an imposing wall of rock rising up out of the sandy ground. "We should get there at least. We need real shelter."

Cas could tell the Winchesters were also fully aware of their need for a safe space to spend the night, because neither of them argued. They exchanged a quick glance, initiating some sort of wordless communication that Cas was too tired and out of the loop to read.

"Okay," Dean finally said. "We'll get to the cliffs tonight, and then we'll make camp. But I want you to tell us if you need to rest. I don't want you collapsing on us."

Cas nodded.

"So you're good to keep walking?"

"Yes," Cas said, but his voice was alarmingly small.

The Winchesters started walking again, although this time both of them slowed their pace so they didn't move too far ahead of him, and checked back every few steps to make sure he wasn't falling behind. Cas could also tell that both brothers were on high alert, scanning constantly for any sign of a threat. Cas was grateful for this, because it meant he could let his mind relax some and just focus on replenishing his exhausted grace.

By the time the sun was setting, they had reached the base of the tall cliffs. It took a few minutes of walking along the bottom for them to spot a satisfactory cave - big enough for the three of them to sleep comfortably, and high enough that nothing would be able to see them too easily from the ground, but not so high that they couldn't get to it.

Cas was simply leaning against the sun-warmed rock and trembling by the time Dean finally pointed out the perfect cave, maybe twenty yards in front of them. Within minutes, they were safe inside, and Cas felt himself sink exhaustedly to the ground, still shaking.

"Take off your clothes," Dean commanded.

"What?" Cas asked, staring up at Dean. He wondered if he had misheard.

"They're soaking wet," Dean said. "You're just going to get hypothermia. Take everything wet off, and I'll get you a blanket. Then me and Sam are gonna go gather wood so we can make a fire."

"I should come," Cas said through chattering teeth, knowing even as he said it that Sam and Dean wouldn't let him. "A dinosaur might-"

"There's no way you can help us with a dinosaur right now," Dean said flatly. "C'mon, Cas, you're blue."

"Dean's right," Sam said, rummaging through one of their backpacks and producing a blanket. "Just...get warm."

Sam had been ready to leave ten minutes ago, but Cas had taken nearly that long to strip down to his boxers and wrap himself in the blanket, not to mention be convinced again and again that it was best if he stayed behind.

"Cas, if a dinosaur came at us, it would think you were a popsicle," Dean finally said, exasperated. "Mmm, frozen angel. Actually, come to think of it…."

Dean produced a canister of salt from his backpack and sprinkled it around the bemused angel, Sam watching with equal confusion.

"There," Dean said. "Dinosaurs can't cross the line. Stay behind it."

Sam quickly looked away, in case he started laughing and ruined Dean's scheme. There was no way Cas was going to believe this….

"Really?" Cas asked, and Sam could hear it in his tone. He was buying it.

"Really," Dean answered. He pointed again at the salt. "Stay."

"We'll be back soon," Sam muttered, fighting to keep himself under control. Before he could lose it, he fled the cave, followed quickly by his brother.

"Dude. I can't believe he fell for that," Sam said, as soon as they were out of earshot.

"I once convinced Bobby that a con man from Georgia stole and crashed his car," Dean said with a grin. "Getting a gullible angel to believe dinos are scared of salt is nothing compared to that. Now come on, let's find some firewood."

Sam gazed at the landscape spread out before them. Behind them were the cliffs, and further back still were mountains, soaring into the sky. At the base of the cliffs, where Sam and Dean were standing, desert stretched out in every direction, punctuated by small shrubs and the occasional thicket of conifer trees. The way they'd come, the trees thickened into a forest around the banks of the distant river.

"Head toward the trees?" Sam asked, and Dean nodded. Sam slung his backpack over his shoulders and they set off.

They spent the next twenty minutes or so trying to gather wood for a fire. It took longer than it would have if they'd been at home, because there were very few tall, healthy trees that could lend them more than a few scraggly branches. Before long, Sam had an armful of dried leaves that he could use to start the fire, but a worryingly small amount of bigger fuel that he could use to actually keep it going. So far, there'd been no sign of any dinosaurs at all. In fact, they only living thing they'd seen that wasn't a plant was some sort of huge bug, which they'd both steered well clear of once Dean had pointed it out.

"We should be heading back soon," Sam said absentmindedly, bending down to pick up a stick. "We have enough to at least get a fire started, and it's not a huge deal if we have to collect more fuel later. I don't think we'll be in any more danger if we go out at night. Maybe we'll be safer, actually. After all, dinosaurs are more active during the day, since they're cold-blooded. At least, I'm pretty sure they are-"

Sam looked up, realizing that Dean had stopped responding. Sam couldn't even hear his footsteps anymore. In an instant, all his senses were on high alert, and he quickly scanned the woods, looking for any sign of what might have happened to his brother.

Then he realized that Dean was standing only about fifteen yards away, perfectly still. The first thing that Sam noticed was that Dean had gathered way more wood than him, and Sam frowned. He hadn't realized it had been a competition, but he should have suspected.

Then he realized that Dean was clearly looking at something. He turned then, as if he could somehow feel Sam's eyes on him, not moving anything aside from his head.

"Sam!" Dean hissed. "Come here!"

Sam started to walk towards Dean.

"Quietly," Dean groaned softly, and Sam's footsteps automatically softened as he moved towards his brother.

"What is it?" Sam whispered, and Dean pointed wordlessly down into a small divot in the rocky earth, still hidden from Sam's eyeline.

"Dinosaur?" Sam asked, but before Dean had answered he was standing alongside his brother, looking at what was very, very clearly a dinosaur.

"It's a stegosaurus, man," Dean whispered breathlessly. "I've just been watchin' it-"

"Oh my god, Dean, get away from there," Sam said, voice rising with his panic. Dean was altogether too close to the dinosaur, and he barely even seemed concerned. Sam had a sudden image of it stomping on his brother, and then possibly eating him. He knew this kind of dinosaur wasn't a carnivore like the t-rex, but would it still eat some meat? How could science possibly know if a dinosaur would be willing to try a human?

"Sssshhh," Dean hissed. "It won't notice us if we don't move."

"Back slowly away," Sam insisted. "Before it sees us."

Dean rolled his eyes, but obeyed. The two of them began to move backwards, inch by inch. And then, the huge reptile's head swung towards them, and it made a low purr of warning.

"I told you to be careful," Dean hissed at his brother, and Sam glared back at him. "Stand very still, it'll lose interest."

Sam shook his head. "No, I think you have to make yourself big, loud, and scary."

Dean shot him a look. "That's bears, Sammy."

"It's large animals in general," Sam insisted, and before Dean could stop him, he leapt to the side and began waving his arms and shouting.

"SAM, NO!" Dean yelled, lunging for his idiot brother, but it was too late. The frightened stegosaurus turned and lashed out at Sam with its spiny tail, catching him along the side and throwing him bodily into a tree. Sam's body crumpled to the ground, and the stegosaurus lumbered off in the opposite direction, as fast as its stumpy legs could carry it.

"Sammy?" Dean breathed, and then he was kneeling beside his brother, holding his breath as he reached out to Sam.

"Ohhhh, you were right," Sam mumbled as Dean touched his shoulder, and Dean breathed out with a rush of relief.

"I have to get that in writing," Dean said with a small chuckle. "Can you sit up? Is anything broken?"

Sam began to push himself up, then stopped with a wince. Immediately, Dean was there, supporting his little brother's weight.

"What is it?" he asked, and Sam frowned.

"My ribs," he answered. "I think I broke a few."

Dean glanced at Sam's torso, giving it a cursory examination. There were two long scratches on his side from the stegosaurus spines, and if Sam said that he'd broken some ribs, then he'd broken some ribs.

"Okay, let's get you up," Dean said, in the same older brother voice he'd been using for over 30 years. Sam nodded and grabbed the outstretched hand Dean offered, and Dean pulled him to his feet.

Sam groaned softly, but aside from that made no complaint. Dean looked closely at his face. He was in pain, but he'd be alright, as long as Dean could get him back to Cas.

"Dude, you got attacked by a dinosaur. Know how many people can say that? No one!"

Sam actually seemed to brighten some at that. "Yeah, you're right," he said, putting a hand on the tree and resting for a second while he caught his balance. "Literally no one who has ever existed can say they got attacked by a dinosaur."

"Except the dudes from Jurassic Park."

"Well...they're fictional," Sam said. "So I don't think that really counts. I think it's just me."

Slowly, Sam pushed himself off of the tree, swaying slightly as his legs engaged to take his weight. Dean hovered carefully around him, ready to grab his injured brother at a moment's notice, but Sam seemed alright, just in pain. Dean watched as Sam put a hand to his side, and winced when he felt the slip of blood against his fingers. He twisted in a vague attempt to get a better look at the wounds, but the angle was awkward.

"How bad?" Sam asked, moving the tatters of his flannel aside, automatically turning to give Dean a better view.

"Not as bad as they could be," Dean said. "You got lucky. Even without Cas, I don't know that you'd need stitches."

"I can live with that," Sam said. He pressed a firm hand to his side in an attempt to slow the bleeding, at least until they could get back to the cave.

"You're okay to walk?" Dean asked.

"Yeah," Sam said, and while Dean could hear in his voice that he wasn't completely positive, he could also tell that Sam wasn't just lying to tough it out, and did believe that he could do it. Dean nodded slightly, satisfied, and proceeded to gather up the wood he had dropped when the dinosaur had charged Sam. No sense making this whole trip worthless, and they still really did need to get Cas warm.

They began to make their slow way back towards the cave where they'd left the angel. Within a few minutes, Sam's left side was alarmingly bloody, but Dean comforted himself with the knowledge that the wounds from the stegosaurus were just long, not particularly deep. The broken ribs were potentially more of a concern, but at this point Sam's breathing seemed completely fine, and Dean tried to force himself to relax. Relax...that wasn't going to be possible with his little brother limping beside him.

"Not much longer now," Dean said to Sam, the words for his benefit as much as his brother's.