A/N: Please note that this was written in September last year, long before The Burning Maze. I kept meaning to share this one earlier except my life gets insane. I decided to go ahead anyway. But this is the last outstanding fic that I have floating around that I'm cross-posting here! Anyway, This was written as a gift for thefangirlinawheelchair as the first-place winner in the percyjacksonweek2k17giveaway. They only request was Jercy, which I tried to fulfil. It's Jercy if you squint? But really just a little bro adventure. Thank you to the pjoweek mod for being my beta on this piece!

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Horse Play

by shiiki

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'Dude, you're lost,' Jason said.

'I am not,' Percy insisted. 'I know exactly where we are. I'm just taking the—the scenic route.'

Jason raised his eyebrows at the sparse desert landscape outside the car windows.

'Well, why don't you try giving me better directions?' Percy said defensively. He tapped his fingers impatiently against the steering wheel.

'Not much point now, is there?' Jason said. 'There's only a straight road to follow.' He groaned, imagining the smug expressions that were sure to be on Piper and Annabeth's faces when they finally met up with them in L.A. It had taken a great deal of convincing to talk the girls into flying there directly and letting Jason and Percy take a road trip down—boys only—on their own.

'They're so getting lost,' Piper had said when they'd dropped her and Annabeth off at the airport.

'Wanna bet?' Percy had challenged.

Annabeth had just smirked as she and Piper got out of the car.

Jason was not looking forward to the I told you so's they were sure to face from the pair of them.

'We should've gotten a sat nav,' Percy muttered.

'Monsters,' Jason reminded him. 'Remember what happened to Frank when he used one driving to Vancouver last month?'

Percy winced. Frank's car hadn't survived that journey. Neither had the sat nav. Monsters evidently tracked GPS signals even better than they did cell phones.

Jason sighed and took off his glasses to clean them on his shirt. When he put them back on and looked up, he nearly had a heart attack.

'Look out!' he yelled.

Too late, Percy slammed on the brakes and jerked the steering wheel to the right. The donkey that had appeared out of nowhere in front of their windscreen brayed and almost went splat. Their car swerved and slammed into a cactus. The air bags went off, ballooning painfully into Jason's nose. It wasn't quite like the bricks people kept chucking at him, but it came close.

Still, he hadn't gotten himself knocked out. Always a bright side.

'Ow,' came Percy's voice, muffled behind his air bag.

Jason reached for the car door and carefully inched himself out of the seat. The hot desert air hit him in the face like an oven's blast.

Outside, the donkey lay on its side, its chest rising and falling with obvious effort. The fender of their poor Subaru Impreza was crumpled up against the cactus. Spiky thorns were scattered all over the hood, which was smoking faintly.

Percy cursed as he emerged from the driver's seat, his hand over his nose. 'It came out of nowhere, I swear—oh gods. Are you okay?'

'Yeah,' Jason began, but realised quickly that Percy wasn't talking to him. The donkey let out a soft, braying moan, and for one ludicrous moment, Jason thought Percy was speaking to it (hey, the guy spoke horse—donkey couldn't be that far off, right?) Then Percy crouched down, disappearing behind his side of the car as though bending over someone.

Jason hurried over to the other side. A teenage girl with black pigtails and a ferocious scowl lay by the side of the car, blinking up at them. Percy tried to help her sit up, but she batted his hand away and pushed herself to her feet without assistance.

Jason would have found this girl strange no matter what—after all, who appeared out of nowhere on a donkey in the middle of the desert?—but her garb compounded the weirdness. She seemed to be wearing a sack—at least, it was a squarish tunic that looked like it was made of burlap. With her long neck and the even longer face she was pulling, she had a distinctly horsey look.

Percy scratched the back of his neck. 'Correct me if I'm wrong, but did you just appear in front of our car riding a donkey?'

'I'll appear wherever I want with whomever I please!' snapped the girl. 'What do you have against donkeys?'

'Nothing!' Jason held up his hands. 'We didn't me to, uh—' He glanced helplessly at Percy. 'Please tell me we didn't actually hit them.'

'You didn't,' said the girl. She jumped to her feet and snapped her fingers. On the other side of the car, the donkey got to its feet, took a few steps towards them, swayed a little, and fell over again. 'Hopeless. A little scare and he keels over every time. Well.' The girl turned back to Jason and Percy, hands on her hips. 'Since you've scared the living daylights out of Dobbin, how are you going to appease me?'

'Appease …?' Realisation hit Jason like a ton of those damn bricks. 'You're a goddess.'

'Well, of course I am! Epona, goddess of horses, that's me.'

'Um. But that's a donkey.' Jason pointed to the concussed animal.

Epona glared at him. 'So?'

'So where's your horse?' Percy looked confused. 'And I thought my dad was god of horses?'

Epona sniffed. 'You must be a brat for Poseidon. Just like him, too. Creates horses, sure, and then forgets all about them. Leaves it to me to care for them and protect them.'

'Hey, I treat horses okay!' Percy protested. 'You can ask my Pegasus.'

'Your Pegasus!' Epona drew herself up. She wasn't very tall, but her posture was so regal, she seemed to add a foot to her height simply by straightening up. 'That's just like Poseidon, acting like they're your property—'

She looked ready to take a swing at Percy—which, as these things often went, would more likely miss and hit Jason instead.

'Okay, stop!' Jason held up his hands between Percy and Epona. 'Goddess, we apologise.'

Percy gave him an incredulous look. Jason tried to signal with his eyes that it wasn't the best idea to mess with a goddess, even one so minor that he as the Pontifex Maximus charged with building shrines to them all (okay, so it was a self-declared mission—it still counted!) hadn't come across yet.

'We really didn't meant to scare your donkey. Is there anything we can do?'

In retrospect, he should have known better than to ask.

Epona's eyes gleamed. 'There is one thing that will revive Dobbin once he's had a shock.'

And as she started elaborating about a rejuvenating weed found at the bottom of a magic lake, Jason wished he'd just kept his mouth shut.

'Let me get this straight,' Percy said. 'You want us to find a lake in the middle of a desert and find some magic weed at the bottom?' He ticked off each task on his fingers as he spoke. 'Why does this sound like another impossible quest to me?'

'Probably because it does,' Jason muttered, still cursing inwardly that he'd even offered. They already had a smoking car and Juno knew how many miles to cover to get to L.A. A quest was not on the to-do list for the day.

He should have just offered to build a shrine or something for Epona. He was already doing a dozen a month, what more was another? Actually, maybe he should just offer …

'Are you sure we couldn't just build you a shrine? Or even a temple?'

'Yeah.' Percy jumped at the idea immediately. 'My bro here's your man for a temple. Custom-made and everything. He'll even bump you to the top of the construction list. Much better than some stinking weed.'

Epona's mouth twisted in a smug, satisfied smile. 'A temple will do nicely,' she said. 'After you retrieve the Glaukosweed.'

Great. Now they had two jobs. Jason rubbed the bridge of his nose, trying to find a different excuse. 'But—but we don't have any transport. I mean, we just totalled our Subaru. How are we going to get to this lake of yours?'

'Ah, yes.' Epona's smile grew wider, becoming almost alarming in its horse-like ferocity. 'How silly of me.'

She snapped her fingers.

Jason blinked.

Where Percy had been standing was now a magnificent black stallion with a messy mane and glassy green eyes.

'I'll teach you to disrespect horses, son of Poseidon,' Epona sniffed.

Percy the horse let out a series of spluttering neighs. Jason didn't speak horse, but he would swear on his father's master bolt that none of what Percy had just uttered was fit for innocent ears.

Epona smirked and turned to Jason. 'Well, then. You asked for transport. I take it you know how to ride?'

'Goddess,' he said hesitantly, 'we still don't know where this lake is—'

And we haven't been doing great with directions so far today, he wanted to add.

'Your horse should be able to lead you to water,' Epona said, her voice thick with irony. 'Go on, then. If you return successfully, I'll change him back.' She considered the smashed-in Subaru. 'And I'll fix up the car into the bargain. Two-for-one. Or maybe two-for-two. You did offer me a shrine, after all.' She tossed her head and smiled like she was appreciating her own generosity.

Jason didn't have much of a choice. He supposed he could always attempt to blast Epona with lightning, but that wouldn't turn Percy back to normal. And quite frankly, he'd had enough of blasting goddesses.

'Right,' he said. He gripped a handful of Percy's mane—Percy whinnied grumpily—and swung himself onto his back. 'Giddyap.'

Percy turned his horsey head to give Jason a distinctly unhorse-like glare. Then he sprang into a raging gallop.

Percy the horse was a much better driver than Percy in person. Or was Jason the driver, since he was riding horseback? Not that he was steering or anything.

Either way, they raced purposefully across the desert sand. There was no saddle, but Jason kept his balance easily, his hands wound into Percy's thick mane and his thighs gripping Percy's silky coat firmly.

'You're not half bad as a horse, bro,' he commented.

Percy gave a snort that he was fairly sure translated into, Shut up.

'You sure you know where you're going?'

The snort became an irritated whinny.

It turned out he did. Either Percy—horse or person—had a natural affinity for tracking water (as opposed to his non-existent ability to find cities), or Epona had implanted a GPS (one that didn't attract monsters, thank Jupiter) along with his transformation, because soon enough, the dark sliver of a lake came into view. Percy trotted up to its edge and neighed softly.

Jason slid off his back. 'This would be easier if I could understand you.'

Percy stuck his head under the surface of the water, lifted it back out, and looked pointedly at Jason.

'You're saying look inside?'

Jason had never seen a horse roll its eyes before, but Percy somehow managed to pull it off.

'Okay, here goes.' He knelt by the lake and peered at the surface. It was dark and murky despite the desert sun shining down on it. Jason wasn't crazy about the idea of sticking his head into some strange body of water—especially not one recommended by a crazy horse goddess—but Percy had just done it with no harm done, so he followed suit. The moment his head broke the surface, everything under water became crystal clear. He could see all the way to the bottom, which sparkled as though the sun was shining right through, illuminating the deepest corners. The Glaukosweed Epona had described to them lay on the lake bed, its fronds drifting lazily up towards the surface.

'Looks easy enough,' Jason said, lifting his head back out of the water. 'I guess we just dive in and grab some?'

Percy shook his mane vigorously, spewing water all over Jason.

'Dude!' He supposed it didn't matter since he'd be getting all wet anyway if he dived in, but still.

Percy neighed.

Jason sighed. 'I still can't understand what you're saying. We should have done this the other way round. At least you can understand horses—no, Jupiter's jowls, what am I saying, I don't want to be a horse!'

Percy gave a soft snort.

'Though I guess you'd handle swimming for weeds better than me with your Aquaboy stuff.' The horse gave him the evil eye, which he ignored. Did horses swim? He couldn't remember. 'You couldn't make the water push up some of that Glaukosweed by any chance?'

Percy stared at the lake surface intently, like he was trying. Nothing happened. The lake stayed obstinately opaque.

'Oh well,' Jason said. 'Okay, I'm going in.'

He briefly considered harnessing a venti as an oxygen mask, but summoning up a breath of wind in this stifling desert heat was going to take way too much time and energy. Besides, the lake didn't look too deep. He could just hold his breath. Dive in, get out—how hard could it be?

Jason removed his glasses, took a deep breath, and dived.

He got to the bottom without issue. It was when he got his hands on the Glaukosweed that things started to get dicey. The Glaukosweed did not like being harvested. Jason yanked on it … and the plant yanked back.

Vines sprang up around him, wrapping themselves around his wrists and ankles. Bubbles trailed from Jason's mouth as he struggled against their grip. A particularly hardy frond smacked his back so hard, it knocked the remaining air from his lungs. He gulped reflexively and took in a choking swallow of stale lake water. Spots danced before his eyes as he gasped for air that wouldn't come.

Styx and Lethe, he should have just summoned the venti.

Above him, a large, dark shape plunged into the lake. Percy the horse was coming for him, legs flailing awkwardly but determinedly through the water. His head arched forward, black mane streaming back along his neck. Percy's teeth were bared and his eyes gleamed as he let out a burbling neigh. Jason didn't need to speak underwater horse to know that Percy was yelling, 'Not my friend, you blasted plant!'

It was the most beautiful sight Jason had ever seen.

I guess horses can swim after all, he thought groggily.

A thick and surprisingly solid frond hit him in the head and he blacked out.

Something was licking his face. Jason groaned and reached up to slap it away. His arms wouldn't move. They were like Imperial gold bricks, too heavy to lift.

The next thing he knew, hands were compressing his chest, forcing water from his lungs.

He threw up.

'Thank Olympus!'

Jason opened his eyes, coughing and wiping his mouth. Percy was squatting next to him—human Percy, looking greatly relieved to see Jason awake.

'You're not a horse any more?' Jason asked weakly.

Percy shook his head and held out a handful of limp, flat Glaukosweed. Out of the water, it looked like a harmless patch of seaweed—nothing like the strong creepers that had had Jason in a stranglehold.

'I had to bite it off to get you untangled,' Percy explained. 'After I dragged you outta there, I was—well, I tried to get you to come round and, er, I was a bit sloppy about it, and I think I accidentally swallowed some. And then …' He gestured at his own de-horsed body.

'Huh,' Jason said. He suddenly remembered the sensation of a rough, wet tongue running over his face. 'Wait, did you—before you turned back, I mean, were you …?'

Percy's face went scarlet. 'Horse reflexes,' he muttered.

'Huh,' Jason said again. His own cheeks felt embarrassingly warm.

A loud snap made them both jump. Epona appeared out of thin air, atop Dobbin the donkey, who was now wearing a bridle and harness, to which their car was attached, looking good as new. Despite not having partaken in the Glaukosweed Epona had claimed he needed, Dobbin looked plenty revived already.

'Horse reflexes, ha,' Epona said in a lofty tone. 'Well, I see you figured out the properties of Glaukosweed. It reverses transformations. I thought it fitting for you to get yourself out of your fix.'

'You mean you turned me into a horse and nearly got Jason strangled just to—to what?' Percy scratched his head, bewildered.

'To teach you a lesson, of course. How do you like answering to a master as horse? And I hope you've discovered that horses are well capable of achieving things humans can't!'

Jason thought she might have gotten things a bit backwards. It seemed like having a horse rescue Percy instead of Percy as a horse doing the rescuing would have better illustrated Epona's point. But he kept his mouth shut. He didn't want to give her any ideas.

'I never said—' Percy began, but seemed to think the better of whatever he was about to say.

Epona waved her hand towards the repaired car. 'Be on your way, then. And don't forget my shrine, son of Jupiter.'

With another snap of her fingers, Epona and Dobbin vanished.

Jason and Percy got back into their newly-repaired car.

'So,' Percy said. 'Let's not ever talk about that.'

'Agreed.'

He gave Jason a sidewise glance. 'Glad you're not strangled by gawky weeds, though.'

'Glaukosweed,' Jason corrected automatically. Percy rolled his eyes and Jason smiled. 'Glad you're not a horse.'

Percy started the car and they got back on the road.

'At least we have an iron-clad excuse for being late—that doesn't involve getting lost,' Percy said after a while.

Jason gave him an incredulous look. 'I thought you said we weren't going to talk about it? You're going to tell the girls what happened?'

'Hades, no! Who said anything about that? We'll just say we ran into a goddess along the way and made a little detour to help her out. Simple. No one got turned into a horse and no one got knocked out—how many times does this make it now?' (Jason made a rude hand gesture at him.) 'Well, no one got knocked out by crazy underwater plants.'

They exchanged a long, understanding grin. What happened in the desert was staying in the desert.

'You know,' Jason said as the desert faded into the distance, 'you did make a pretty splendid stallion.'

'Shut up, Grace.'

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A/N: Epona is an actual patron goddess of horses. All inaccuracies and exaggerated interpretations are of course mine. As for Glaukosweed—completely made up. But Glaukos is a fisherman in Greek mythology who was turned into an immortal after eating an unnamed herb!

And yes, I know this is kind of bittersweet for some of you. This is what I get for letting life get in the way of putting these up before big canon-balls come to blow my old fic out of the water.