"Twilight Sparkle!"

The voice rang out from behind her. Twilight turned, and broke into an even wider smile at the sight of Princess Luna, the lovely diarch of the night. "Yes, Princess? Is there anything the matter?"

"Ah... nay, it is not so." Luna hesitated, instinctively scuffing her hoof slightly on the rich red carpet that lined the castle corridor. "Art thou - are you visiting my sister once more?"

"Mmh! I am!" Twilight confirmed brightly.

"You have been visiting her a great deal, of late. Indeed, I would say that you live here far more than Ponyville," Luna probed gently.

"Well, I could say that we had a breakthrough," Twilight replied coyly. "We're a lot closer, now."

Luna hesitated, on the cusp of asking a direct question, then thought better of it. "Well, I am most glad that the two of you are enjoying each other's company so much. Indeed, the two of you - on those rare occasions when you are not alone together within my sister's chambers - are positively radiant."

Everything that Luna was saying held the warmth of approval and gladness, but somehow, there was just a hint of something else beneath. An uncertainty. She glanced down at Twilight's chest, with a faintly puzzled look, then as swiftly looked back up again. "I, ah - I shall hope to see you both for supper."

"That sounds lovely. See you later, Princess!" Twilight told her brightly, then skipped off down the hallway, her short skirt coming perilously close to showing her ass with each bouncing step. Slipping between the stoic, straight-backed guards, Twilight let herself into Celestia's suite of personal chambers and shut the door solidly behind her.

"Who is it?" rang out Celestia's familiar voice.

Twilight giggled with delight, and called back, "A slutty, brainless fuckdrone!"

"Good. Come here."

With quick, eager hands, Twilight pulled her jumper over her head, and began wriggling out of her skirt, tossing her clothes carelessly to the ground. She wasn't wearing any panties beneath, her legs clad in sleek stockings that led to a lacy garter belt, her cunt and round ass bare and ready for use. Reaching behind herself, she undid the fastenings of her chest-binder one by one, sighing in relief as it finally sprang free and slithered to the ground.

"Ohh, that's better," she murmured, hefting her new, magically-enlarged tits in her hands. "I hate having to wear that thing. It's so confining." It hadn't been easy finding the right spell to alter herself as Chrysalis had demanded, and even more difficult to make the ancient, obscure enchantment work, but the results were more than worth it: now she looked like the fuckable slut she had always been destined to be. Her fingers slid lower, caressing the tattooed words that now decorated her mons; 'Property of Chrysalis'.

"I am waiting," came the voice again, more sharply.

"Coming!" Twilight sang out, and all-but ran towards the other mare's voice, her big, round tits bouncing heavily, nipples already achingly stiff. Letting herself into Celestia's bedroom - or what used to be Celestia's bedroom - she dropped to her knees before the towering, imposing figure of the Solar Princess. "My Queen! How is she doing?"

The pale white mare laughed, a hissing, sibilant sound. "See for yourself," she replied, with a flick of her horn. The heavy oaken wardrobe opened wide.

There were no clothes within. No shelves, nor rails. Instead, there was another Princess Celestia, nude, scrawled with insulting words, her ankles and wrists chained to bolts screwed deeply into the ancient, iron-hard wood. A thrusting, pumping mechanism was between her legs, ramming twin thick dildos in and out of her cunt and ass; the slick, gleaming mess of innumerable orgasms soaked her parted thighs. A bright red ball-gag kept her lips parted, drool running down her chin and forming rivulets down the slopes of her heavy tits. Small, vibrating beads were taped to her nipples. A tall posture collar forced her head to stay up; a heavy blindfold completely covered her eyes, and a black iron ring was lodged around the base of her horn.

She, too, had the words 'Property of Chrysalis' tattooed above her cunt.

Twilight sighed longingly, squirming with arousal. "I love what you've done with her. She's been in there for three whole days; if she wasn't already your totally mindfucked cunt, she would be by now!"

"She can take a few days more," purred Chrysalis in Celestia's voice, reaching out to roughly knead one of the captive mare's breasts. Celestia whimpered, her ever-present low moans rising in pitch to something more urgent as she was touched.

"Luna is getting suspicious," Twilight said earnestly, clasping her hands in front of her and squeezing her large, soft breasts together between her arms. "I think she's noticed there's something off about you and the way I'm acting, and she might have noticed the binder earlier. It feels like she's working out there's something more going on than just me and Celestia fucking. She's probably going to start watching our dreams closely, if she hasn't already."

"Then it's time I break her, the way I broke both of you," Chrysalis replied with lazy satisfaction. Turning her head towards the groaning, drooling mare, she addressed her more directly. "I'm going to take your sister. I'm going to break her mind, make her a whimpering bitch slut that lives to serve her Changeling Queen. Just like I did to your precious student. What do you think of that?"

Yet again, with a muffled, ragged cry, Celestia came.

Author's Note

The spell Twilight ended up using on herself requires the bodily fluids of a changeling - not only is it extremely hard to cast, but the reagents just aren't available. As a piece of magical lore, it was incredibly obscure. But, faced with a demand from her Queen, Twilight is very talented, and was very, very determined to succeed.

Thanks again to DbzOrDie for commissioning the art for this piece at my specifications; it's gorgeous, and I love it.

• Proofing and suggestions by Equimorto and DbzOrDie