“Uhhh... My head...” Rarity says, still in a daze. Something feels off. She swings a hoof, nothing but air. This comes as a shock to her, removing any trace of drowsiness she previously had. Rarity is in a harness, suspended over a pool of a foul-smelling sludge. Upon one of her legs is a shackle, which appeared to be anchored by chain in the middle of the rancid mire. A staircase off to her left seemed to lead up to the ceiling, but with no visible way out. An earth pony in a cage hangs opposite of her.
“Well, well, the fair Rarity awakes...” a familiar voice calls.
“You again? What more do you want with me, you fiend?” She asks pointedly. The magic screen returns, and the visage of the unicorn puppet along with it.
“Just a game, my dear, but I doubt you are in a position to decline.”
“Well, get on with it, then.”
“Certainly. The rules are simple, you and the pony before you are trapped in this room. Only the key hidden in the muck you see below you can free you, but only one of you. The choice then, is yours. Do you free this stranger in a generous act of self-sacrifice? Or do you act only in your own interests and save your own skin? You have twenty minutes before this room floods, taking the both of you with it.”
The ropes keeping her suspended went slack, dropping her into the foul substance. “Ewwwww” Rarity shrieks, completely horrified by everything she had just experienced. “I think I'm going to be ill!” she cries, as a sickening feeling washes over her. After a few moments of deep breathing, she manages to regain her composure, although not entirely, as she was still standing in the disgusting collection of filth. “Well, no use standing around” Rarity says to herself to steel her nerves, as she begins to tap at the ground with her hoof, in search of the key.
“Oh, please hurry” the pony in the cage says pleadingly. She continues her search, when her hoof contacts something hard, but it doesn't feel like a key. A puzzled look crosses her face as she grabs hold of it with her magic. She lifts it out of the muck and immediately retreats from the sight. It is a bone.
“I-i-is that a-a-” the caged pony stammers. She regards the bone with an abhorrent look on her face. Her heart begins to race as thoughts of the sludge’s contents do so in kind. Her magic dissipates, and the bone disappears into the mire. She runs off to the staircase so she can take a moment to collect her thoughts. But as she gets close, the chain grows taut, and she falls into the sludge.
Rarity jumps to her hooves after her fall, more unnerved than she had been. “It'll be ok, just calm down, we'll find a way out of this” The caged pony calls out to the nervous mare.
Heaving a deep sigh, Rarity responds, “Yes... You're right... I just have to find that key.” In that moment, holes open up in the ceiling and a large amount of sludge pours from them, filling up the room a good deal more than it had been. The horrid gunk, which had previously been about knee-high, was now higher than her shoulders. “I'd better hurry, it seems” Rarity says, nervously staring at the new level of muck.
She continues her search, when her hoof strikes something hard, smaller than a bone this time. Her heart soars as she lifts the object from the sludge, to discover that she had indeed found the key. “Hmm...” Rarity hummed curiously as she studied the key. It didn't seem any different than any normal key. She needed to test something. She then fishes around nearby in the hopes of finding a bone.
“I hope whoever this was won't mind me doing this...” Rarity says as she transforms a section of the bone into a replica of the key. “This had better work...” she says anxiously as she moves the bone key to her shackle.
The tooth of the key goes in and a mechanism inside snaps the end of the key off. Rarity gasped and pulled out the key tooth. “So that's what they meant by that...” Rarity then goes to place the metal key into the keyhole.
“Wait,” The pony calls out, “are you sure that's a good idea?” The key goes in, and it taps against the back of the keyhole. Nothing. She is hit with a burst of inspiration and removes the key. She holds her shackled leg to her ear and strikes the metal band with the bone. Rarity makes note of the sound, and does the same with the key. It's the same sound.
“Aha! I've got it!” she declares as she brings the key back to the keyhole in her shackle. As the lock clicks open, the mechanism snaps off the tooth, and seals it into the lock.
The ceiling at the top of the stairs opened up, revealing a way out. The pony in the cage eyed the opening cautiously and asks, “you're not gonna leave me, are you?”
“Of course not, how could I ever do something so heartless?” She then transforms one of the chain's links into a copy of the key. Rarity walks over to the cage and says, a slight degree of uncertainty in her voice, “Oh, I do hope this works.”
At that moment, another deluge of the fetid goop pours down from above, knocking Rarity off her feet, and with it, the key. “Oh no!” she exclaims as it falls into the muck. The amount of sludge dumped in this time was even greater than last time, it was now about half full. Rarity now had to try to swim in the sludge to keep her head in breathing room. She glances over at the cage. Even it is partially submerged, with the pony inside up to their neck in the stuff.
She took a deep breath and dove into the mire, and began blindly striking at the ground, in search of the key. After a short while, she could no longer hold her breath, and surfaces. Two more times she tried, both times ending in failure. “It's got to be around here somewhere” Rarity says desperately. Another torrent of sludge rains down from above. The room is soon going to run out of air.
She took another breath of air and dives into the muck once more. She searched in desperate hopes of finding the key, going so far as to stay down in spite of her lung's protests. As her body struggles to take in oxygen, her hoof struck the key, and in a burst of elation, she grabs the key and returns to the surface, gasping for air. She shoves the key into the lock. Nothing happened. The key turns and the lock clicks open, and the cage door swings open. “Thank you!” the pony says, briefly hugging Rarity.
The two then made their way to the staircase. They ran out of the room and the door closes behind them. “Glad to be out of that mess, huh?” Rarity says, turning to face the other pony. But there is nopony to be found.