One big perk of being a goddess? You get to live forever.
One definite NON-perk? No matter how long you live, the world never runs out of problems that need your attention.
If you're as responsible as Twilight Sparkle, you learn to take a long-term view of things.
Sometimes the long view means even MORE work. You deal with problems most ponies would never imagine.
***
Twilight's current protege walked into Twilight's study. Brilliant Moonglow looked nervous, shifting her weight from hoof to hoof.
Twilight smiled gently. "I'm glad to see you back, Moonglow."
"Thank you, Princess." The unicorn still seemed uneasy.
"So, my little pony...how was your trip? Are you upset about something?"
"I renewed the spells on the Gates of Tartarus. And I inspected the cages. Everycreature is in their place."
"Good, good. I'm glad to hear that. But is something troubling you? You can always talk to me."
"How do you know..." the unicorn's quiet voice trailed off.
Twilight replied softly, "How do I know what?"
"If somecreature belongs in Tartarus. Creatures in Tartarus are trapped there forever, in the darkness and the cold and...the most awful, nasty company. Even if they escape, they always get put back pretty quickly. With the special enchantments on Tartarus, they can't even look forward to the ultimate escape of death. They will never journey to the Realms After."
Twilight sighed. "That's part of the deal between Equestria and the powers beyond this world. I have to hang on to a few especially evil creatures, to protect the Realms After from the kind of inhabitants they don't want."
"But how can you know?" Moonglow asked. "How can you know, which creatures truly deserve to be put in such a terrible place?"
Twilight remembered a special and terrible day, many years ago.
***
The amber-colored unicorn Sunset Shimmer bowed deeply to Twilight. "I am happy to serve Equestria in your time of need, your highness."
From her royal throne, Twilight returned a bow nearly as deep. "You have come a long way to help Us, Sunset Shimmer. Both personally and in Our most official capacity, We are most grateful."
Casually, almost without seeming to, Twilight eyed the magical pendant which hung from a string around Sunset's neck.
Sunset asked, "So...what do you want me to do?"
Twilight reached into a set of saddlebags which lay over the arm of her throne. She pulled out an oblong rock.
Sunset stared. "Is that what it looks like? I thought it had been destroyed! You...you couldn't want to erase my memory? What have I ever seen? What have I ever DONE to you?"
"Do not fear," Twilight said. "I will do nothing to you against your will."
"What is that thing FOR? Why do you even HAVE it?"
"It's a secret almost nocreature knows. Originally, more than one Memory Stone was created. You can understand the necessity of keeping it secret."
Although she feared the Stone, Sunset forced herself to stay calm. "I know we wouldn't want anycreature to abuse it. Or to even think about trying to steal it, I guess." Her nostrils flared. "But why is it here?"
Twilight asked, "Sunset Shimmer, do you know anything about Tartarus?"
Sunset nodded. "It's the most secure prison in Equestria. The cages hold dangerous creatures like Tirek, Grogar, and the bugbears. But it's not only for strange creatures with monstrous shapes. Even a regular pony can be put into Tartarus, if that pony's heart is evil enough. And unless there's an extraordinary disaster, nocreature can ever escape from Tartarus, not in a thousand thousand years."
Sunset grimaced slightly. "I could tell you more, of course."
Twilight replied, "No need, Sunset. You understand the seriousness of this occasion."
"What occasion?" Sunset asked. Behind her, Sunset heard creaking and rattling. She dodged to one side of the large room, as a score of royal guards pushed and pulled a cart, on top of which a pony was chained.
Sunset looked on in amazement. "That's a lot of chains for just one pony."
"Yes," Twilight agreed. "But this pony's evil deeds outweigh all of those chains. You don't want to know everything this pony has done."
"Oh," Sunset said, putting two and two together. She raised one of her forehooves, almost touching her necklace. "But YOU want me to know."
Twilight nodded. "Equestria NEEDS you to know. There are so many ponies in Equestria. Nocreature is perfect, of course, but most are basically good. Even some ponies who do great wrongs are still, deep in their hearts, pained by their wrongdoing. Usually, at least a small part of such a pony is trying to struggle towards right."
Sunset thought. "I sense an oncoming 'but,' your majesty."
"Even the smallest thing, the tiniest bit of appreciation of good, can help lead a pony back towards the right path. A pony who loves his child, might start to see how other ponies are also worthy of love, or at least kindness. A pony who does one good deed, might feel that other good deeds are also worth doing."
Sunset sighed. "So you want me to search this pony for even the smallest speck of good."
"And afterwards," Twilight said, pointing one hoof at the Memory Stone beside her, "I will offer you the relief of forgetting what you found."
For a moment, Sunset said nothing. "I think it could be terrible, looking into such an evil pony's mind. But I suppose if I don't do it, your other options are even worse."
Twilight said in a soft voice, "You understand. I am so sorry to ask this of you."
Sunset snorted. "I'm sorry you have to ask this of anycreature." She walked to the wagon. With one hoof she touched her pendant. Her other hoof barely touched the chained stallion.
A lifetime of evil flashed through Sunset's mind, as fast as thought. She felt all of it.
Sunset's face contorted with pain. The pain twisted into rage. After only a moment, she pulled away from her torturer, and said in a nasty voice, "That stallion...I've never felt so much hate."
Twilight asked in a tone every bit as soft and mild as Sunset's was harsh, "Is there any good in him? Any love? Any kindness? Any ability to see some of the good this world offers, and maybe someday build on that bit of understanding?"
Sunset's face looked like an evil mask. "No. Burn him to ashes. Burn him forever. Place a spell of eternal life on him, just so you can torture him again and again--"
As the alicorn princess watched her friend spew hatred like a demon, like somepony whose inner self had been twisted into perverse shapes by a lifetime of evil...Twilight touched her Memory Stone. Bolts of magical energy flashed out towards Sunset and the guards. A final flicker also struck the prisoner's head, to erase all memory of the pendant and the Stone. All the targeted ponies slumped, losing consciousness. Twilight put her Stone back into the saddlebag.
Twilight told herself, don't worry, you used the Stone soon enough. You might have made Sunset turn herself into something terrible, but only for a moment, before you let her forget. She didn't have to bear that burden for long at all. There's still time for her mind to unbend, back into its proper shape.
I'm pretty sure I didn't break her.
And before sending that stallion to an eternity of suffering, I had to know. Somepony had to look.
After a minute, Sunset Shimmer slowly got to her feet. Her expression had changed from almost demonic, to innocent confusion.
"Wow," the sunlight-colored mare said. "What happened?"
Tears leaked from Twilight's eyes. "Nothing you need remember." The princess trotted down the steps from her throne, and hugged Sunset. "I am so, so sorry. My little pony, I am unworthy! The things I've had to do, trying to keep Equestria safe!"
Sunset's hooves gently patted Twilight's withers. "I'm sure it can't be that bad. Maybe you have to make some hard choices, sometimes. But I trust you. I know you do your best, to do the right thing."
Twilight sobbed.
As the guardponies pulled and pushed the wagon out of the room, Sunset hugged her friend harder.
Sunset murmured, "I don't know what you feel so terrible about. But whatever you did, it seems like you're suffering from it as much as anypony else ever has."
Twilight shook her head from side to side, like a horse trying to shake a fly out of her eye and failing. "No. I must never tell myself that comforting lie."
While keeping her forehooves on Twilight's shoulders, Sunset pulled back just far enough to look the princess in the face. "The things you've had to do...are those ponies still suffering? Or have they found...peace?"
Twilight snorted, a bitter look on her face. "I suppose the ponies I've been most unjust to for the good of Equestria...they've found some peace. They've been freed from their pain, one way or another."
"Well then," Sunset said. "I'm glad that even if they were in pain, it didn't last forever."
"Of course it didn't. I don't imagine anypony could bear that kind of pain forever." Twilight sobbed. "They would break. Harmony forgive me, they would break first."
Sunset went silent, letting Twilight cry herself out.
***
"It's a difficult process," Princess Twilight said without providing any details. "Searching a thoroughly wicked pony for even the smallest trace of good isn't easy."
Moonglow looked at Twilight admiringly. "I think in some ponies it wouldn't take long at all. Your good shines out like a sun. You make all of Equestria a brighter place than it would otherwise be."
The corners of Twilight's mouth wrinkled. "It's kind of you to say so, Moonglow."
"I say it because it's true!" Moonglow insisted.
Twilight didn't argue.
Instead, she asked a question. "Moonglow, I sense you had something more specific you wanted to talk about."
Moonglow pressed her lips together tightly.
"Maybe you DON'T want to talk about it." Twilight contemplated. "Perhaps you would like to SHOW me something?"
Moonglow nodded.
***
During the journey, Moonglow had spoken only of the smallest, least consequential seeming things. Twilight had only been able to infer the destination by her knowledge of Moonglow's most recent previous errand, and by the supplies the protege had requested.
When Twilight and Moonglow reached the Gates of Tartarus, Twilight let her student unlock the entrance herself, with a skillful little spark of magic into the keyhole.
As the pair walked into Tartarus, Moonglow tossed three large dog biscuits to three-headed Cerberus, who caught them in his mouths, grinning at the visitors.
Moonglow's horn lit up. "I think I can do this..." Moonglow's body sprouted a pair of wings. They were shaped and colored exactly like the wings of a dragon, complete with scales.
"Sweetie's Lesser Dragonflight," Twilight remarked.
"Yes. I was reading the history of your early reign, and your friends...and one thing led to another."
Twilight smiled. "I'm sure Sweetie Belle would be happy to have her spell remembered. She invented it as part of an apology to her friend Scootaloo."
Moonglow remarked, "Other flight spells are easier, or prettier, or fancier in other ways. But this is the longest lasting, most durable choice I know."
Twilight nodded approvingly. "So, do you want to take a flight?"
"No," Moonglow said. "I want to take a walk, first."
Moonglow led Twilight through Tartarus, between strong steel cages and deep, smooth-sided pits. Different monsters and ponies peered at the visitors, eyes gleaming in the darkness wth anger or spite or, sometimes, weariness.
The two ponies walked past a muscular pony who slowly pushed a round boulder up a long slope, towards the top of an underground mountain.
"Who's that?" Moonglow asked.
Twilight squinted in the near-darkness. "That's...his parents named him Sassafras. But he preferred to be called The King of Thieves, or King Slipperyhooves."
"Why Slipperyhooves?"
"He bragged that no matter what he did, nocreature could catch him and make him change his ways. He said he was above all laws, and beyond all standards of right and wrong. He said he would just slip out of their grasp every time."
"If nocreature can catch him, why is he pushing that rock?"
"Compulsion spell," Twilight said. "It's like the Want-It-Need-It spell, but with a little twist. Getting that rock to the very top of the mountain, and keeping it there, is what he wants most. But he can never have it. The mountaintop is too smooth. Whenever he gets near the top, he slips and tumbles back down the mountain, with the rock rolling after him."
"Ouch," Moonglow said.
"A protective spell keeps him alive, and keeps him from getting crushed to death. But if a boulder runs over his hooves, I'm sure it still hurts."
The dragon-winged pony watched Sassafras push his boulder. "I guess he was a bad pony. But why did he deserve to be punished forever? Laboring for something he can never have, not even for a moment?"
Twilight frowned. "He started with little things...things that were more like pranks than real crimes. But he was so proud. Just to show off, he tried doing things that were a little worse, so more creatures would try harder to catch him."
Twilight shivered. "After years and years, between trying to show off and trying to stop anycreature from catching him, he did some things that were very bad. If you knew everything he did...it could drive you half mad, just knowing. He finally turned into a monster."
The prisoner changed direction. He had been pushing his boulder towards the top of the mountain, but now he was pushing it more diagonally. He took it partway down the mountain at an angle, as if he'd become confused. But before he reached the mountain's bottom, he remembered his goal, and struggled slowly back up the slope.
He must have gone mad, Twilight thought. He literally could no longer remember which direction was up.
Twilight shivered again.
Moonglow asked, "Are you cold, Twilight? Should we go back outside, into the sunlight? Where it's warmer?"
"It's nothing mere sunlight will help. Let's just find whatever you wanted to show me."
Moonglow flapped her leathery wings, and flew.
Twilight followed.
***
As the two ponies soared, Twilight looked down at the stony floor. "I've never thought to look at Tartarus from this particular angle. Goes to show, when you think you've seen everything, maybe you haven't."
Moonglow explained, "I flew when I visited here last week. I thought a pegasus's eye view would be a good way to check on everything. And I think I was right. Notice anything? Any changes?"
"I've never seen Tartarus from the air before. How would I know if anything had changed?"
"How long have some of these prisoners been here, Twilight?"
"I don't know. Almost since the world was new, I suppose. Some of them were here long before I was born. Maybe before Princesses Celestia and Luna were born. The history of those times is so fuzzy, it's more like legends. Hard to know for sure."
Moonglow said, "Some ponies have funny ways of talking about eternity. Until the oceans dry up, until the mountains wear out...that kind of thing."
Twilight snorted. "I think we have a while to wait yet, before that happens."
Moonglow led the way higher.
"Careful," Twilight warned. "We don't want to hit the roof."
"I think this should be high enough." Moonglow flew in long, lazy circles. Twilight followed her.
Twilight noticed something on the cavern's floor. Somepony had carved shallow grooves into the mountainside. Some of the grooves formed simple, abstract-looking shapes. Other grooves formed an image of a mare's face and neck, and a little of her shoulder.
The mountain's smooth, steep peak formed the tip of the unicorn mare's horn.
Twilight gasped. "How lovely."
Sassafras pushed his boulder near the edge of the mare's image, slowly wearing a new path to someday depict more of the mare's shoulder.
Twilight stopped beating her wings, gliding in slow circles downwards.
When Twilight landed, Moonglow landed next to her.
"Twilight? Are you crying?"
"Sockdarned right I'm crying." The stone beneath Twilight's face gleamed with drops of moisture. "There's more than one way to escape a prison. The best way to escape...is to find something good in the world, even if it's only a memory. Something nopony can take away from you."
"You saw the picture," Moonglow said. "I didn't know what to tell you."
Twilight shook her head slowly. "This is the best way you possibly could have found to tell me."
"It's a nice picture. But I don't know what the simple grooves next to it are. Maybe practice for the mare?"
Twilight shook her head. "I guess almost nopony nowadays would know. But I'm thousands of years old, and I still remember Middle Ponish runes. These spell out one word: sorry."
"Oh!" Moonglow said.
"We thought Sassafras was completely full of evil. Sunset--the reader who looked at his mind, reading his life like a book--she became so angry. So full of hatred. I had to erase every bit of her memory of what she'd seen inside him. Otherwise, I feared, she might rip herself apart with pain and rage. She might become a monster like him. But maybe, just maybe...deep down, nopony was as angry at Sassafras as the King of Thieves himself."
"Twilight...what are you going to do?"
Twilight stood up straight, and marched towards Sassafras. Her horn lit up, striking both Sassafras and his boulder with a powerful bolt of magic. The stallion stepped sideways, letting his stone roll downhill without him.
"Are you sure this is safe? Twilight!"
The stallion walked towards Twilight, knelt down before her, and shuddered. "Sor-ree." he said. "Sor-ree."
Twilight said, "I know it was thousands of years ago. But how much can you remember?"
"I did bad things. I didn't want to get caught. I did anything I had to, to stop them from catching me." He shuddered again. "To keep from getting caught for the bad things, I did even worse things." He lay limply upon cold stone. "Until all I could do was get caught. I hated myself so much, by then."
"What would you do next time? If you had another chance?"
"I would do anything, to keep from becoming a bad pony again."
***
Twilight wanted to let Moonglow go ahead, so the princess-goddess could speak privately with the old criminal. Moonglow wanted to send for a full brigade of royal guards, to oversee the prisoner release along with anything else that might need overseeing or guarding.
The princess and her protege compromised. Moonglow came along, but just far enough back that she couldn't easily overhear a whisper.
"It's over, Sassafras. It's finally over. We've both won."
Twilight led Sassafras to the gates of Tartarus. She unlocked them, and let him out. He walked across the grass, marveling at the world he hadn't seen in so very, very long.
Sometimes he stopped to take a few bites of grass, or even a tasty flower. As he chewed, he took more steps.
Twilight watched him slowly walk away, until he was lost among the distant trees.
"Goodbye," she whispered. "And congratulations. One of us is finally free."
Author's Note
The idea of a fimfic about Sisyphus got batted around a bit. As it turns out, different writers' hands can turn "the same idea" into very different stories.
The idea of Sunset Shimmer reading Sisyphus' entire life in a moment was inspired by (chapter one of) Scampy's "Synthesis," which I guess was inspired by shortskirtsandexplosions?