The time difference between the UK and Cruciatu meant that it was quite early for the girls. There was no rush before their first day of training would begin, no rush at all.

All in all, Claire was delighted with the surgical team. She'd worked with them before of course and she knew that any of the clinical team at Cruicio Prime was more than worth their ridiculously generous salaries, but she had selected the staff for Penny and Amy's treatment specially: Nurse Taylor because she knew that the blonde would gel perfectly with her own plans to add to Penny's torture with mind games and mockery, and Nurse Lucy for Amy because the woman was almost merciless, and revelled in the more subtle psychological aspects of absolute domination.

Throughout Penny's torture and modification, Claire couldn't help being distracted by the way Nurse Lucy placed with her charge. Working almost in the dark so that no tiny glimmer of light could possibly pierce Amy's blindfold, working without assistance so Amy could hear absolutely nothing, the brilliant black nurse combined exquisitely pleasurable teasing and stimulation with sudden bursts of inexplicable pain that must have come from absolutely nowhere, at least as far as Amy was concerned. While Claire could watch Penny's heart rate rise and fall, almost mapping her horrible experiences through the sudden sharp spikes as her helpless body was reshaped to Claire's warped specifications, Amy's pulse raced constantly, her whole body in a state of constant panic as Nurse Lucy turned even pleasure into a silent promise of pain. Amy's physical modifications might have been less devastating than Penny's, but Claire was confident that the psychological damage and sense of absolute fear would be far, far worse.

The first real chance to assess whether that was true came when the girls were prepped for the great unveiling. With no earthly reason for Penny or Amy to keep the sorts of hours humans normally enjoy, Claire had the occasion staggered so she could watch live in the UK as the sisters slowly struggled back from beneath the blanket of drugs and returned to the eternal, living hell Claire had condemned them to.

Amy woke first, whimpering and moaning, still utterly blinded, and Claire had her left like that until Penny also began to burble through her gag, before dialling back the opacity of their vision entirely.

The two women yelped simultaneously as the bright lights suddenly glared into their eyes, but already their responses were different - Penny shied away, flinching and trying to twist her head in the posture collar, eyes scrunched tight until she adjusted to the dazzling brightness. Amy, on the other hand, merely yelped in pain and shock, blinking repeatedly, but doing her absolute best to keep her eyes open, her body still. Simply allowing Claire to blind her vision despite the pain, as if Amy couldn't imagine being able to writhe away, and so didn't begin to try.

Which is why it was Amy who saw the state of her own body first. And began to sob.

"Noh! Gohd. Whad... What habe yuh dunh?? Whyyy??"

Her voice, broken by misery and rusty from so long kept silence took a moment to register with her sister, but when it did, Penny's eyes flew open with a gasp of "Ayhmee!!"... And then a long, shocked silence as Penny stared at the reflections in the mirror, the colour steadily draining from her face as her eyes almost bulged with shock, roving up and down her abused body in growing disgust.

Strapped to the cross as she was, the obscene ruination of Penny's already fleshy cunt was obvious: the eight massive rings hung down, stretching her delicate inner lips beyond any normal range thanks to the effects of the Spatium. Each pair constantly twitched as its magnetic field interfered with those of the rings next to it, and the constant quiet clicking and shifting of the almost microscopically serrated steel had caused poor Penny's lips to swell, while the steady stimulation of the thick twitching hoop forced through her bloated and trapped clit left the poor woman almost literally dripping wet, adding a fresh layer of obscenity to the sick sight.

The posture collar kept Penny from looking down, but even if she had tried her reflection made it obvious she'd see nothing but her massively swollen udders if she tried. Her always impressive cleavage now bulged, a weight so severe it took her physical effort to hold her back against the X she was shackled against, and capped with monstrous steel cones that were visibly warping her already thick nipples into genuine fat teats that wouldn't have looked out of place on an animal, never mind how unnatural they seemed on a woman.

The whole sight was enough to make Penny vomit, and for a while she simply stood, struggling and gasping, trying to keep her clenching stomach under some kind of control before she looked across to her sister... And felt a pang of almost pure envy at how easy Amy had it.

Yes, her breasts had been ballooned in the same was as Penny - although still she was being expected to bear less weight than her big sister - but where Penny's piercings were grotesque steel monsters, Amy's looked almost decorative: six labia rings instead of eight, and all done in small, almost delicate golden hoops, while even Amy's nipple stretchers seemed to be more modest, elongating Amy's buds without the brutal, straining urgency imposed on Penny's udders.

"Claiiihre!!" Penny howled - and even she couldn't have said if it was a scream of horror or a roar of outrage "Cklaiiree houw cudh youhh?! Whad hag youh dunhh?? Whyyyy?! Hough cudh youh be sho cwuel?! Pleagh!! Oh Ghogd my poohr cundt!! My lipsh... I... Oh Ghogd. Led ush goh! Pleagh. We musht hag shuffergd enuff by nowh. Pleagh... Pleagh..."

And she fell silent. Simply staring at the unrecognisable mockery of herself, and sobbing.

Savouring the absolute horror the girls were experiencing, they were left there for over an hour to contemplate their situation.

Small garbled attempts of communication between the sisters were attempted, but nothing came of it as both girls were eventually overcome with the visions of each other and devolved into choking, slurred sobs.

For the last few days all Amy wanted was to escape the crushing blackness of the isolation hood. All that time deaf and blind, she reasoned if she could just see and hear she could prepare for what was coming, accept it better. If she was allowed to speak she could tell whoever was doing this to her that this was all a mistake, to beg them to stop.

Nothing could have prepared her for this. Never in her most deranged nightmares could she have imagined something like this happening to her. In her damaged mind she could still barely believe it. It had to be a nightmare? The way her vision just came back to her instantly, that wasn’t normal. Was she in hell, now some demons plaything? How could they have done this to her breasts? They still stung and burned terribly.

For Penny, she had accepted the changes a little more but it didn’t make it easier. Her mind was more concerned with what was coming next. In the van, she thought it couldn’t get any worse. Then the private hell of the shipping container which led to her first torture session at Claires private prison as they injected and pierced her. She knew that the changes made to her were to assist in some other part of Claire’s plan, but it was too terrifying to imagine that her mind shut down at the prospects.

After what seemed like an eternity,a tall, well tanned, woman in a black latex leotard and thigh high boots entered, accompanied by a well toned man in regular shorts and a workout shirt. The odd duo were grinning from ear to ear. They looked the girls up and down, taking their time to investigate both quietly with just their gaze before directly locking eyes with them in the mirrors.

“Good morning my dear ponies’ purred the women, positioning herself behind Penny and coming in very close, scraping her finger across Penny’s inner thigh and locking eyes with her in the mirror. “I am Mistress Kaya and this…” she gestured to the impassive man who stood with arms crossed “is Trainer Leo.”

“We have been assigned to your ponygirl training regime.”

The mistress circled Penny, slowly dragging one of her nails up and across her back.

“I spent many years in the equestrian world...but normal horses are so boring.” she continued around the front of Penny, as she continued dragging her nails across her sore red tits.

“Cruciatu sought me out with a ludicrous offer and now I spend my time here, breaking naughty girls like you. Teaching you form and discipline using methods that are banned in the real world. I’m not really into animal cruelty...” She pouted “...but using some of the tools that Crucitu gives me on unbroken slaves like you makes me fucking wet” She stopped in front of Penny and pinched both caged teats greedily, sucking and biting at her lower lip.

If Penny had been given a hundred guesses as to Claire's plans for her she would never once have imagined a woman referring to her as a pony.

That there was some sick sexual side to Claire's sadistic vision was obvious enough - even now, after all the horrors she'd experienced, Penny still felt a surge of revulsion as she remembered Claire's obvious, lustful masturbation to the sight of Penny and Amy screaming as they were tortured. But... ponies...

Her skin crawled in revulsion at the hungry, predatory way Mistress Kaya fondled her flesh, the firm grip on her bloated breasts making her whimper through the gag, and the obvious gleam of cruelty as the trainer spoke of wet she got using tools on women that she wouldn't dare use on animals...

"Whad gare yuh tawking abhoud?" Amy sobbed "Igh'm nod a pohwnee! Igh'm a wummhan!! Jushgt leg meeh goh, I habend't dunh anyfing, pleashe!! Aaauughh!!"

SMACK!!!

The poor girl broke off whimpering as Trainer Leo slapped her tight arse violently, leaving a stark red print on her smooth olive skin, and Penny felt a guilty surge of relief that Leo hadn't assaulted her poor ass in the same way: the possibility of her cheeks clapping around those horrible studs chilled her blood even to imagine.

“She's interested in form, I’m interested in performance” The man spoke plainly and loudly.

“I was a Personal trainer in America before I landed this gig. I’ll be making sure that we push your bodies to maximum everyday so you can keep up with Kaya's demands. The Madam has told me to pull out all the stops to get you hitting your stamina limits every day. This isn’t some gym session you can pull out of if you get a little puffed and need to catch you breath. You will WORK. You will PERFORM. YOU WILL OBEY.” The man was getting red in the face yelling at the girls. “You will be drilled daily until you drop, then you will be punished until you get back on your feet. From sunrise to sunset. You will be trim and toned beyond belief after this. I’m sure we can figure out some way for you to thank me"

The playful mistress nodded knowingly “We make a great team. I am form and he is function. There will be no escaping us or your training. Don’t think we’ll be going easy on your because of your fat tits either, you’re just going to have to learn to cope with them.”

“Mmmm time to go girls. Lets show you what being a pony is all about”

Leo unclipped Amy’s arms and started binding them behind her back, while Mistress Kaya grabbed a thin chain from the wall and clipped it to Penny’s erect clitoris while running more of the chain through Penny’s legs, making her rings jingle. As Amy’s leg shackles were removed she was pushed over to Penny and the other end of the chain was attached to her clitoris ring as well.

With Kaya leading the way she pulled the girls out of the room and down a hallway that didn’t look like the medical ring, with Leo strenly watching Amy from the rear, keeping his eyes on her pert ass while he imaged how tight it would becom ein the coming months.

It was the first step the girls had taken and the overwhelming new sensations caught them off guard. Both could not believe the weight and balance different their new breasts gave them and as they stumbled forward they both felt their new metal jewellery accentuating every feeling they felt from their womanhood.

Uncaring, the pony mistress led them on towards the end of the hall where ponies were starting their long day.

With the heavy chain adding even more weight to Penny's throbbing clit, and the cruel way it threaded back between her hanging cuntlips to hook around her sister's dainty clit-ring as well, every step was agony for Penny, made worse by the unnaturally heavy weight of her newly enlarged udders, swaying ponderously before her until she felt her own back cramping from the effort of adopting her old posture.

Every step caused her thighs to rub against the massive steel rings and set the sickeningly serrated steel grinding against the piercings, keeping Penny's stretched and sagging folds constantly stimulated and irritated, forcing her pussy to drip juice in a desperate attempt at self defence so that every movement milked her juices and made her moan. At the same time, any stumble jerked her clit-chain and shot white hot pain through Penny's entire body, almost ensuring she would stumble again, her massive tits jolting and tugging her more and more off-balance, and at the same time jerking the chain linking her to her suffering sister's clit so that Amy howled in as much pain as Penny, creating an echoing duet of agony that rang out as they stumbled along the hall.

For now Mistress Kaya left them to it - it was no way for a pony to walk, but she wanted both women to find their balance and get used to walking in their usual way as quickly as possible - it made it far more likely they'd make mistakes born of old habits in training, and punishing mistakes was one of Kaya's greatest pleasures.

As she walked, sobbing, begging for mercy, squealing whenever Amy's stumbling steps strained her stretched and throbbing clit, Penny kept waiting for Claire's voice. She was so used to it now she was almost growing dependent on Claire as her last link back to her old life.

But Claire, watching silently on her screens and teasing her swollen, soaking sex as she watched Penny's agonising procession down the passage, kept herself firmly muted: right now it was essential that Kaya and Leo had the floor, and had the pleasure of revealing the full horror of where the girls were heading.

So Penny walked in silence, too lost in her own pain to realise that Claire was silently dialling down her vision so that both she and Amy could only see a few feet in front of them. Ensuring that their experience at the end of the hallway would be as shocking and horrible a revelation as their first sight of their twisted new bodies.