It had been a long hard day, filled with surprises, trials and tribulations, and Applejack could feel even her fabled earth pony endurance beginning to run out. As she stepped forward again, a tug reminded her that there was another pony on the end of her tether, literally. Looking back, she could see Rarity following closely behind her, not that Rarity had any choice in the matter.

The normally proud and somewhat vain fashionista had found herself harnessed, hooded, bridled and bitted following a run-in with an old machine called a “Unicorn Breaker '' and as a result was now wholly dependent on Applejack for… everything.

And to her own surprise, Applejack found herself loving every minute of it. She loved the way Rarity hung on her every word, loved how responsive the unicorn was to each and every twitch Applejack made on the guiding reins, and she loved how Rarity had decided to call her, “Mistress”. The power of being in dominant control of such a vital and vibrant creature like the fashionista was a heady wine and it had gone straight to Applejack’s head with thoughts of all the wonderful things she could do with Rarity.

Which also meant taking care of the exhausted unicorn.

“Hang on there, Rares,” Applejack said loudly. “Ah think Ah smell water up ahead. If there is, it’ll be a good spot to rest a spell.”

A quiet nicker was the only response Rarity gave, having given up trying to form coherent words around the bit that held her mouth open and her tongue down. Tired as she was, it was easier just to keep walking and only respond when she needed to.

Applejack led the pair through a narrow gap in the stone passageway and paused in surprise as they entered a huge grotto. The ceiling arched high upward into an eternal darkness beyond the light of the glowstones the ponies’ had, while the bottom of the cavern spread out wide before them. Off to one side, Applejack could see a large pool of water, nearly a small lake in size, and even what looked like an old camping site beside it, complete with firepit and a small stack of what looked to be coal..

“Hoo Wee, we hit the jackpot!” Applejack declared, urging Rarity forward with a gentle pull on the reins. “Just a bit farther and you can have a good rest.”

A minute later, Applejack was tying off Rarity’s reins to a hole carved into a stone and then quickly went over to check the water. The two of them could last quite awhile once they ran out of food, but only a day or two without water. A quick taste assured the earth pony that the water was indeed good to drink and as she turned back, Applejack was forced to pause again.

Rarity was sitting on the ground, head bowed. The various glowstones Applejack had hooked into her chain harness glowed like a constellation of emeralds, lending an otherworldly and submissive beauty to the fashionable pony. Applejack swallowed to clear a suddenly dry throat before deliberately diverting herself with setting up camp.

For Rarity the day had gone from a fun outing with a friend, to near mortal peril, to being rendered completely helpless and at the mercy of another. Considering it was Applejack who had her as a helpless captive, Rarity had happily thrown herself into the role of a submissive slave mare who had been sold off to a stern yet kind mistress. However, as the day wore on several things combined to make Rarity’s position less a role and more a reality.

First off was her dependance on Mistress Applejack for direction and guidance. With a hood of fine chainmail covering her eyes and most of her head, she couldn’t see a thing and had to rely on Mistress’ guiding pull on the reins for all direction and guidance.

Second was the dildo that had been screwed into her pussy through one of the broad links that cleft the cheeks of her ass from top to bottom. The evil device locking into place on the ass chain had ironically been the key to releasing her from the clockwork that had bound her in the harness in the first place. As Rarity walked along the shaft slid back and forth against her sensitive walls, doing its level best to ignite a fire in her loins.

Worse, the shaft had an imitation of a medial ring that kept tapping against Rarity’s G-spot, both stimulating her and reminding her that she was a bound captive, who was not only unable to control her baser urges but was not allowed to control them. And to top all of that off, roughly every five to ten minutes the dildo would rumble away inside of her for roughly a minute or so before coming to a stop.

Combined, the dildo had turned Rarity into a hot, sweaty, needy mess of a mare whose every other thought was about how badly she wanted Mistress to bring her to a stop and put out the fire in Rarity’s pussy with her tongue or her hooves or… anything. Anything at all.

Third was the bit that trapped her tongue down and her mouth open, which had the effects of making certain word sounds impossible and causing her to droll a great deal. Eventually, Rarity had given up the unequal struggle to sound like an intelligent being and had reverted to the grunts, nickers and neighs of a beast of burden. All of which were perversely ungarbled by the oval metal rod locked to the back of her mouth.

All told, the pony that had been Rarity Belle at the start of the day was now a blind, inarticulate animal who was wholly dependent on her Mistress and was literally aching for some form of release from hours and hours of low to mid-level arousal.

“Easy girl,” came the voice that the bound pony had been heeding for hours, followed by the soft touch of a wet cloth.

So heated was Rarity, that the cool cloth passing over her head and along her back was like a cold fire that seared away all conscious thought, leaving only the blissful pleasure of relief in its wake. Back done, Rarity was unresistant as she was rolled onto her back, moaning as the gentle touch of her Mistress continued to spread the wonderful coolness onto her chest and belly.

Applejack paused the sponge bath she was giving Rarity for a moment. She’d only meant to clean her friend a bit and give her a bit of a cool down, but the open mouthed moans that let Applejack see the whole of the bit in Rarity’s mouth were more than simple relief. Much, much more, and with Rarity on her back and cushioned in the earth pony’s lap Applejack could see and smell just how heated the unicorn had become during their subterranean hike.

Applejack knew that the two of them were at a crossroads, and while she tried to resist the urge to take advantage of the beauteous mare in her thrall, a treacherous thought reminded her that Rarity had literally asked for this. Had asked Applejack to take possession of her. That there was no other pony she would rather give her reins to.

Almost without thought, Applejack soaked the cloth again and began to use it to gently caress Rarity’s teats, bathing them in the cooling waters, and the unicorn’s reaction was immediate and wanton.

“Ah Ah!” Rarity wordlessly cried out, arching her back and pressing her lower body up against Applejack’s circling hoof.

Applejack’s head swam with feelings that seemed to reach deep inside of her, to touch her very soul. The feeling of power she had over the writhing beauty in the grasp of her chains, her control over Rarity’s responsiveness to her every touch, of how the harnessed pony shifted her hips back and forth to try to grind her teats against Applejack’s hoof, and it was in that moment that the earth pony truly accepted her role as Rarity’s mistress.

“Yer mine, aren’t you?” Applejack asked huskily, feeling desire fill her even as she moved the cloth to scrub away the sticky residue of hours of unfulfilled arousal that coated the area around Rarity’s labia.

“Pweath!” Rarity mewed in her need, desperately trying to push the dildo trapped within her even deeper.

“Hey, none of that,” Applejack commanded, pushing aside Rarity’s reaching hooves, and the whine of complaint from the white mare was followed by an answering growl. “Ah’m in charge of you, you do what Ah say, when Ah say, and right now Ah’m saying you aren’t allowed to get yourself off.”

A pleading sound of garbled words and desperate need for fulfillment escaped from the chained throat of the mare. A noise both inarticulate and clear as a shout. Rarity would do anything, anything at all, if only Applejack would quench the fire in her loins.

“Now don’t you worry none. Yer mine, and Ah take good care of what’s mine,” Applejack said, as her hooves began to move in deliberate circles over Rarity’s clit and nipples.

Due to the chain that cleaved Rarity’s slit, Applejack wasn’t able to get a hoof direct onto her target, but the buttery smooth links easily slid over the raised button of flesh beneath them, and as the chain moved on its slight amount of slack, it caused the attached dildo to twist and churn inside of Rarity. Rarity’s moans and cries of delight were like music in Applejack’s ears, driving her to “stir” up her pony even harder, leaning even further over the white mare’s body.

“Pweath!” Rarity begged again, and as fresh nectar began to leak out around from the dildo Applejack moved forward until she was standing low over the length of Rarity’s body.

“Not yet girl, you can’t cum y—” Applejack broke off as a soft muzzle began to nose its way into her own soft folds.

“Clever girl,” Applejack murmured, as the generous mare beneath began to give as good as she had been receiving.

Rarity’s tongue began to caress Applejack’s own delicate nub of flesh, drawing it out with gentle licks and flickering teases with the tip of her tongue, and the burning heat between the bound mare’s loins began to be joined by an equal fire from within Applejack. A smell like sweetly stewed apples began to rise from the sugar walls of the earth pony, prompting Rarity to plunge her nose even deeper into her mistress, who responded with gratifying moans of her own.

“Sweet Celestia!” cried out Applejack, increasing the intensity of her own ministrations, spreading Rarity’s lower lips even further to try to get as much access as she could. “Just… just drive in for the core, why don’tcha?”

Rarity’s generous nature and need to please the pony that was doing her best to pound her plot with tongue and shaft drove her to plunge in as far as she could into Applejack’s tunnel, creating a flow of syrupy goodness that thoroughly coated the muzzle of the unicorn. Thick and heavy oozed the nectar of the aroused earth pony, rich with all the fertility and potential that was the hallmark of all earth ponies, and the Apple clan in particular.

For her part, Applejack’s efforts were being steadily rewarded with a fresh flow of Rarity’s own juices, oozing out from around the orichalcum dildo that Applejack was now repeatedly pistoning back and forth along Rarity’s chain barred passageway. It was only an inch or so of movement, but combined with what Applejack was doing to Rarity’s teats and clit, it was a very important inch of movement.

Rarity’s mind had been mazed with both exhaustion and low level arousal before the duo had arrived at the campsite, but now, the tidal waves of powerful stimulation and overwhelming sexual energy served to drown all conscious thought from the unicorn. For the unicorn, there was no “Rarity” anymore. There was only a pony, who only felt pleasure and the need to give it in return, an animal who was bound to serve the one who held her reins and be rewarded in turn.

It was a race then. A sexual race of arousal and desire to see which pony could bring the other to their finish first. Applejack had the advantage of the low level edging that Rarity had been suffering through the day, as well as having a dildo in place that was literally made to drive a pony wild. Rarity however, was able to plunge herself deep into Applejack, spreading the earth pony wide with her muzzle and her flicking tongue that seemed to touch every pleasurable nerve in Applejack’s core.

The two ponies writhed around as they licked and sucked and fondled each other, creating a strange music of moans, gasps and small outcries of pleasure. A small syncopation of the chains and rattling pendants fastened to Rarity sounded a rhythmic counterpoint as both the bound unicorn and her earth pony worked at each other's bodies to the best of their abilities.

“Rares! Ah’m close!” gasped out Applejack, causing Rarity to redouble her efforts and stepping up her attack by bringing her hooves into play as well.

“Ah AH!” gasped the earth pony, working the shaft locked in Rarity’s pussy for all she was worth, driving it with all the speed and force of a stamp mill running at full capacity, and it was the sledgehammer that shattered the last of Rarity’s control.

A massive whinny exploded from Rarity as she came with the fury of a small star, juices gushing from her in a torrent as her long pent-up orgasm finally tore free from a place deep within her very soul. That cry of realized pleasure echoed within Applejack’s womb like an earthquake, triggering an orgasmic avalanche that ended with her own devastating climax moments after Rarity’s, her own flow of nectar being so thick and heavy that the unicorn had to suck and swallow desperately lest she drown in the tide.

Slowly the two ponies drew apart by the barest amounts, panting for breath as they did so, the swell of afterglow filling both of their thoughts with a pleasant golden haze of pleasure. A pleasure that refused to fade, but instead spread through the bodies and limbs of the pair, settling into a lethargy akin to being covered by a warm, soft blanket.

Eyes drooping, orange and white fur merged as Rarity and Applejack came together again, snuggling against each other and nuzzling gently with soft sounds of sleepy endearment. Both ponies had been through much that day, and sleep came to them both on swift wings.

Some time later Applejack awoke, stiff and sore from sleeping on the hard ground and a need to answer the call of nature. With all the care she could muster, the earth pony disentangled herself from her partner, at one point stopping just in time to prevent herself from tripping over Rarity’s reins, which were still looped through the rock they had been attached to.

By the light of the body heat driven glow stones Applejack made her way over to one side of the cavern and dealt with her body’s needs. As she turned to head back her eyes fell on the sleeping mare that was now hers in nearly every sense of the words. Love, affection, worry, combined with a strong desire to protect the chained alabaster beauty rose up within Applejack, and as Rarity gave a slight shudder in her sleep it was all Applejack could do not to sidle up against her once more.

The thought of taking those reins in her hoof again, of pulling Rarity against her and driving her unicorn into a frenzy again filled Applejack’s mind with pleasant thoughts, but the practical nature of the earth pony asserted itself. There were chores to be done, and Rarity was depending on her to get both of them through this.

Applejack had anticipated the need for torches or a fire on their journey through the subterranean caverns, and had made a point to salvage some of the rotted cloth and timbers from the remains of the “unicorn breaker”. It took some coaxing, but the farmer managed to kindle a small fire into life, which she slowly fed bits of coal until they too came to life.

Fire going, Applejack set a pair of apples to roasting on wooden spears while she had a quick dip in the cavern’s pool in order to wash off. Emerging some minutes later, she found that Rarity had been awoken by the fire and rolled onto all fours, orienting herself toward the fire by feeling its heat.

“You okay there, Rares?” Applejack asked. For some reason it felt right to call her pony by the diminutive instead of her full name.

A gentle nicker and bob of a hooded head was Applejack’s answer.

“Don’t feel like talking?” the earth pony asked, and the mute answer was a wide opened mouth that allowed Applejack to see the green gold bit that crossed Rarity’s maw, with its attached spoon keeping her tongue pinned.

“I getcha, hard to even try I bet,” Applejack commented, which garnered a confirming nod. “Well food’s about ready.”

Applejack was forced to chuckle as Rarity’s stomach growled an answer.

“Here, hold out yet hooves. It’s roast apple on a stick,” Applejack said, waiting until Rarity obeyed to give the warmed treat with its attached holder to the bound pony.

Mission accomplished, Applejack wasted no time in sinking her teeth into her own apple, with its slightly caramelized flesh almost melting in her mouth she could practically feel her energy levels climbing in response. With almost savage relish the earth pony took another bite that halved the apple, shearing it almost in half. A sound of deep satisfaction came from Applejack, but as she lined herself up to annihilate the remnants of the fruit another sound came to her ears.

It was a sound unlike any Applejack had heard before, a sound of frustrated misery. An anguished growl that ended with a hiccoughing sob of anguish. Turning, Applejack saw that Rarity had taken a single bite out of her apple, but instead of consuming the nourishing food, it instead lay on the ground in half masticated chunks.

“Rares? What’s wrong, girl?” Applejack asked, moving to lay beside her captive almost before the faint echoes of Rarity’s complaint faded away completely.

Mutely, the enslaved fashionista opened her mouth again, pointing with a hoof to the bit with its attached spoon.

“I don’t get it. Show me,” Applejack gently commanded, holding the apple up to Rarity’s mouth.

With the care befitting her usual nature, Rarity took a bite from the apple, and how the chained mare accomplished the usually simple task gave her mistress all the information she needed. Instead of closing her teeth completely, Rarity’s bit and bridle were allowing her mouth to only close most of the way, forcing the unicorn to rip the piece off with a small toss of her head.

“That bit isn’t letting you close your mouth all the way, is it?” Applejack asked, receiving an affirming nod. “And cause you can’t close yer mouth all the way, you can’t chew that apple right, and the spoon on the bit ain’t letting you swallow either, is it?”

The second piece of the apple fell from Rarity’s mouth as she shook her head despondently, and Applejack could see tears sliding out from underneath the close-linked chainmail hood bound to Rarity’s head.

“Don’t you fret none, Rares,” Applejack stated confidently. “Ah’ll figure this out. Ain’t no pony o’ mine going hungry. No sir, no how.”

Applejack began to ponder on how to feed Rares while the white unicorn settled down and patiently waited. The earth pony first considered making an apple broth or soup and pouring that down Rares’ gullet around the bit, but lacking a cooking vessel that was impossible. Other ideas came and went, but they were all either impractical or were like the soup idea, impossible due to lack of tools. After several minutes, inspiration came to Applejack in the form of the times she had helped Fluttershy with some of her bird friends.

“Okay Rares,” as Applejack had taken to calling her pony. “I’ve got an idea. Do ya trust me?”

In response, the harnessed pony rolled onto her back, hooves up to her chest to reveal her soft white belly and throat.

“Ah’ll take that as a ‘yes’,” Applejack replied. “You just stay like that, keep yer mouth open and whatever ya do, don’t fight me at all. Just let me do what ah gotta do to get food into ya.”

An open mouthed nod was Applejack’s answer as the earth pony bit off the rest of her apple into her mouth, but instead of promptly it Applejack instead continued to chew, turning the fruit into mush in her mouth. Then, pulling Rares into her hooves, she pressed her mouth to the bitted mouth of her property, and began to push the masticated apple into the unicorn’s maw.

Despite being warned and wanting to obey her mistress, the captive unicorn began to struggle and fight. However, Applejack was not only an earth pony, but a pony who worked and exercised daily and whose soft coat hid sinews of iron with a will to match. Rares was no match for Applejack’s strength and the reins on her bridle prevented her from moving her head at all.

With the unicorn fixed in place, the mashed fruit passed over her bit to the top of her throat, and for a moment the unicorn convulsed as her gag reflex was triggered, but the sweetness of the apple told the unicorn what was happening and through a supreme effort of will she managed to suppress it.

Applejack felt the unicorn go limp in her hooves as she forced herself to relax, and daringly the earth pony lifted one hoof off the unicorn’s body and used it to work Rares’ chain covered throat, encouraging the muscles there to swallow. And swallow they did, pulling the nourishment down into the hungry pony who was by now in desperate need of calories.

Applejack couldn’t help but feel possessive pride in the unicorn. Rares was submitting herself utterly to Applejack, allowing herself to be used in the deepest ways possible. Even more than the previous day's intimacy, even more than the wearing of a bridle and collar, this was the unicorn surrendering her body utterly to the will of her mistress and the sweet perfume of Rares’ arousal began to fill the air around the pair.

The feeding seemed to go on forever as Applejack continued to push semi-solid apple down into her pony, using the full mouthed, deep throated kiss that conquered the mouth of the pliant and submissive unicorn. At last, the final bits of the fruit were passed through, and as Applejack went to break the lip lock, she felt her unicorn’s hooves snap to action, wrapping themselves around her body.

Applejack let Rares take control for a few moments, enjoying the feel of the fashionista’s chains grinding against her as the unicorn made an attempt to get herself off using the harness along with its attachments. Sadly for Rares, she was most definitely not the one in charge and Applejack had a strong sense of priorities.

“None of that now,” Applejack gasped out, a string of saliva connecting the two mouths as the earth pony used her superior strength and the leverage of the reins to pull back the head of the unicorn. “We got a long way to go and not a whole lot of supplies to get us there with.”

A needy whine and a grind of hips against hips was the answer Rares gave.

“Maybe later,” Applejack said, drawing a hum of pleasure from beneath the chainmail hood as she nuzzled the point of the unicorn’s jaw. “But we gotta get going.”

The only further delay was Applejack leading her pony into the cave pool for a quick wash, and then two set out again. As they travelled Applejack realized that the path they were following was one that had been well used in the past, complete with rest and resupply locations. Sadly, all of the supplies were long since rotted with nearly every piece of metal rusted to uselessness. The only exception being a long coil of orichalcum chain, which seemed to be immune to the passage of time.

The end of the “day” found the pair at another rest stop with a small supply of coal and an underground spring for water. In the warmth of a coal fire, Applejack gave Rares a second intimate feeding that led directly into another bout of passionate lovemaking causing both ponies to fall asleep in each other's hooves.

Upon waking Applejack and her unicorn shared the last of their food before setting off in what they both hoped to be their final day of travel, though in truth both ponies could no longer tell whether it was day or night outside. They were lost in a timeless void where all that mattered was each other. Some hours later however, their voyage of the pair bid to near its conclusion as Applejack began to see reinforcing timbers again.

“Just around this corner, Rares,” Applejack was saying. “We gotta be close to the surface now. Any second and we’re gonna be— Aw shoot.”

Rares gave a nicker of annoyance as she walked into Applejack’s rear.

“Ah.. Ah’m sorry, Rares. The tunnel’s collapsed. We’re maybe a hundred lengths from the entrance, but it's full of rocks and dirt,” Applejack explained, dropping to sit on the cold stone floor. “Ah got no idea how we’re gonna get through that.”

Rarity’s answer was to summon up her magic in an attempt to blast their way out. An attempt which lasted the length of one choked off breath as the orichalcum harness, collar and bridle contracted in response to the touch of the arcane, strangling the attempt to use mystic force before it even had a chance to act.

“It was a good try,” Applejack said, comforting the recovering unicorn as she sucked air back in as the orichalcum loosed its hold on her throat. “Ah’m gonna try to dig us out. Maybe Ah’ll get lucky.”

“Perhaps the pony would like to make a deal?” asked a voice from out of the shadows.

“Who’s there?” Applejack demanded, spinning around.

The eerie light of the harness mounted glow stones illuminated the form of a truly ancient diamond dog as he stepped out from a hole he had just made in one of the tunnel walls.

“Who are ya, and what do you want?” Applejack demanded again, pulling Rares behind her.

“Rock Hound wants to make a deal. An old deal. You are Apple clan, yes?” asked the old dog.

“Yeah, Ah’m an Apple, what of it?” Applejack asked, her voice unflinching and uncompromising.

“Rock Hound’s grandsire told him of old pony deal. Of Vermin, who sold horn head ponies to diamond dogs so pack could find gems. Rock Hound wants to buy,” stated the sibilant voice of the old dog. “You are Apple clan. You have pony.”

“No deal. She’s mah pony,” stated Applejack. “Ah ain’t selling her. No way, no how.”

“Not even for a way out of tunnels?” Rock Hound asked, smiling slyly. “You give Rock Hound horn head and Rock Hound will dig through cave-in for you.”

“No way. We’d rather star—” Applejack stopped as Rarity put her hoof against her owner’s mouth.

“Ik's ekay. Sell ne ke hin, and khen cene hack fer ne,” came the garbled voice of the generous pony, offering herself so that her friend could get free.

Applejack instantly balked at the idea however. Not only did she flat out refuse to sacrifice one of her friends to save herself, but Rares… Rarity had been counting on Applejack to get her out of this, letting Applejack lead her, feed her, command her, love…

Applejack wasn’t sacrificing Rarity. Period.

“Ah’ll make you a counter-offer,” Applejack replied, taking a moment to think. “You open up the tunnel and me and my pony will both come back here in two weeks to help y’all mine gems for a day.”

“Rock Hound could just wait until you are too hungry to stop Rock Hound from taking horn head pony,” countered the big grizzled hound.

“Ya could,” Applejack reasoned. “But then you would have to feed her back up until she was strong enough to do anything for ya. This way, you get two strong ponies working for ya for a day.”

“Three days,” the old dog shot back, which made Applejack smile.

“Two days, and you feed us,” Applejack counter-offered.

“Done,” replied Rock Hound, holding out a paw.

“Done,” Applejack responded, touching hoof to paw to seal the deal, and less than an hour later the pair once more walked in the light...

Author's Note

And now, for the epilogues