The forest surrounds you, black and foreboding.  Dark leaves rustle in the wind.  A storm is coming, and night is falling.
 
You are a human warrior, and you are exhausted.
 
“It’s not much further,” Moss Moon says, her golden eyes faintly luminous as they catch the dying light.  She’s hurrying you through the brush, taking you to the base of the Foal Mountain.  “We’ll stay dry if we can just make it to the road.”
 
You have no such luck.  A few minutes later, the skies open, and a steady drizzle soon turns into a torrent of freezing rain.
 
Stumbling through the dark woods, you follow after the gray shadow that is your companion.  She weaves past wet brambles and gnarled trees, stopping to help you through.  In some places the vegetation is so thick that you have to crawl to get by.
 
The constant stops make for slow going, and you are drenched with rain and mud when finally you reach the base of the mountain.  A sheer rock face climbs high above you, vast and imposing, its upper reaches vanishing into the night.
 
Moss Moon stops here, her hoof resting on stone, eyes searching the mountain as if trying to read it like a book.  After a moment she nods and sets off to the left, hugging the mountainside.  “This way!” she calls, over the pounding of the rain and the steady groan of the wind.
 
You squint, struggling to see, as you reach the beginnings of the ancient road.  A carved path, worn smooth by time, ramps steeply up the side of the mountain.  After a few hundred meters it slopes into the mouth of what looks to be a cave.  Moss Moon trots inside, and you follow suit.
 
It’s completely dark.  You can hear her shivering as she digs through her bag.  A moment later: the sound of two objects being clacked together.  Then there is a spark, a flame, and rosy light spills into the cavern.  
 
The mare is holding a burning torch in her mouth.  She passes it over to you.  It’s made of wood, and you notice a faintly pink-colored substance coating a rag tied around the tip.
 
“What’s this on the end?” you ask.
 
“Sunroot resin,” Moss Moon replies, her answer muffled as she goes back to digging through her saddlebags.  “You dry it out, powder it, then mix it with water to make a paste.  It’ll be good to burn for a few hours.”
 
Next she gives you a bottle of frothy black liquid and tells you to drink just a little.  The substance is cold and very bitter, but you can feel energy filling you despite your fatigue.  Moss Moon takes a few swallows before slipping the bottle back into one of the inner pouches of a saddlebag.
 
The rosy glow of the torch illuminates the road ahead as it curves up and around the mountain.  Carved into the mountainside, the road is covered on all sides by thin rock.  Flickering light reveals flowing arches cut at intervals into the walls, obviously shaped by carvers of long ago.  Rain drums on the roof.
 
Moss Moon meanwhile is looking out the entrance, into the stormy night.  “We can’t stop here,” she says.  She turns to give you a weary and apologetic look.  “The moon’ll be full in three days, and we’ll need time to rest before we climb up the last road.  Will you be okay to travel through the night?”
 
You nod and yawn at the same time.  “Lead on.”
 
She brushes by, idly resting a hoof on your leg as she scoots past, and adjusts the position of her bags.  “Keep that light close.  There might be earthcrawlers in here, but they’ll leave us alone if we have that.”
 
The two of you begin your ascent, following the first of two ancient trails in your journey.  Your companion had described them to you earlier in the day.
 
“I don’t know who built them, but I think it’s been a long time since anypony’s really used them.  It was Grandmother who took me the first time, before her eyesight got too bad to make the trip.”
 
“The first one is just a covered road that goes up and around the mountain.  The main path will take us to the other side, but there are lots of smaller paths that branch off and go deeper into the mountain.”
 
“We want to stick to the main road for sure.  It’s really easy to get lost in there.”
 
“Once we make it to the other side, it’s only about a day’s walk to the next road.  That one isn’t covered, but it’s much less dangerous.  It’ll take us up to the Spring.”
 
You follow Moss Moon, the torch casting its light on the worn path rounding the mountain.  Occasionally you see rain pattering on the ground, coming in through places where the roof has eroded.  Your thoughts gravitate toward “the other side.”  You’ve never been this far inland before.
 
Rain drips off the hem of your worn cloak, while Moss Moon’s coat is plastered to her body.  Your legs are leaden with weariness, and you know she must be tired as well, but she hardly shows it.  Doggedly she leads you up the road, her steps resolute.
 
If only you could be so focused.  You need something to occupy your tired mind.  You search for a question, and settle on the most obvious one.
 
“So why is it that you want to go to the Spring?”
 
The mare is quiet for a little while before she answers.  “A few weeks from now, the foals in the Stronghold will start getting sick,” she says.  “This happens every year.  It’s a wasting illness that paralyzes the body.  Many of them die, or come out crippled if they survive.”
 
She pauses as the road makes a sudden, sharp turn, inclining up toward a long ledge.  The ledge is open on the side, letting in rain and wind.  You can see nothing in the darkness outside, save the vague blackness of the treetops far below.  The two of you huddle to the side, in the thin dry alley where the rain does not reach.
 
“There is a remedy,” the mare continues, raising her voice to be heard over the wind.  “I have to mix salt from Hollow Shades with water from the Lunar Spring, and let the solution bathe in the light of the full moon.  If the foals drink it, they’ll be cured.”
 
It seems strange to you, but you suppose you’ve heard stranger things.  “How does it work?” you ask, as lightning flashes, and a roll of thunder follows.
 
The flame of your torch flickers in the wind, casting dancing shadows on the walls of rock.  Moss Moon dips her head.  “I don’t suppose you’re a believer, Anon?”
 
You simply shrug.
 
The mare turns to look past you, into the dark of night.  “Grandmother taught me that there is a Goddess who sleeps inside the moon, who reaches us through our dreams.”
 
You’ve heard of this Goddess before; many bat ponies you’ve met seem to believe in her.  “So the moonlight is some sort of magic?”
 
Moss Moon shakes her head.  “I don’t know.  It’s not like what unicorns can do.  If it really is a Goddess, then her power works in a way that I don’t know enough to explain.”
 
You both reach the end of the ledge, where the opening closes and the path bends once again upward, climbing ever higher up Foal Mountain.  The sound of the storm recedes behind you, replaced by the dull, steady drum of rain overhead.
 
“What about the salt then, and the springwater?”
 
“The salt comes from an underground stream that flows inland a few hundred miles from the sea.  Some mineral must leach into the water as it comes in.  As for the Spring…”
 
She breaks off as you come to a split in the path.  A tunnel branches into the earth, winding raw and narrow into the deep dark.  Your companion points with a hoof.  “Do you see how rough the stone is?” she asks.  “If you ever get lost in here, always look for the smooth paths.  That’s how you’ll know you’ve made it back to the main road.”
 
You nod in understanding, and wait for her to continue.
 
“Anyway…” she says, after a few moments.  “The Spring has a number of… unusual properties.  For instance,” she points at your wrapped shoulder, “a wound like that would heal in just a night, if you were to drink from the Spring directly.”
 
“Why directly?  Aren’t you planning to bottle it?”
 
“Bottling only works because of the process behind it.  The salt and the moonlight will make it ‘keep,’ but only for a little while.”
 
“How do you know all this?”
 
Moss Moon sticks out her tongue and gives you a teasing look.  “That’s a secret.”
 
You feel a smile edging on your lips.  “Don’t you try to bamboozle me.”
 
She laughs, a pleasant kee-kee sound, before falling quiet again.  Her hooves clack softly against the stone floor, in time with the heavy footfalls of your boots.
 
Now on both sides you see the occasional tunnel spiraling off into the depths.  Your torch illuminates them only partly, the light fading into dark, bottomless holes.  You feel queasy looking into them.
 
After a few minutes you hear a low rumble, which you at first believe is thunder, before you realize that you can no longer hear the rain.  Then the ground begins to shake.  Moss Moon stops you, huddling close by.
 
You feel your heart begin to beat faster as the tremor grows in intensity, rattling the bones of your legs, making you grab your sturdy companion for support.  But just as the fear begins to set in, the tremor slows, then dissipates into nothing.  The mare breathes a sigh of relief.
 
“Earthcrawler,” she says, looking up at you with her huge eyes.  “Don’t worry, they won’t bother us.”
 
Despite her comforting words, you still feel uneasy as you resume your steady upward trek into the mountain.  Even Moss Moon looks slightly unsettled, her eyes traveling warily from tunnel mouth to tunnel mouth as they pass by.  Strangely, you feel your head starting to hurt.
 
Eventually she speaks up again.  “Grandmother taught me a lot,” she says.  “When she was young she used to travel to the other side all the time.  There are lots of things left over there that nopony’s found yet.  One day she found a trove full of books, and she spent a few months ferrying them back over to Hollow Shades.”
 
“At first she wouldn’t let me read them, but when she started going blind, she decided to teach me how.”
 
“What was in them?”
 
Moss Moon smiles again, obviously pleased to discuss the subject.  “Oh, all sorts of things.  It’s written in an old language, so I can only understand part of it, but there’s so much to learn about.  Ponies used to know so many things.”
 
“The only one we’ve mostly finished translating is a scientific codex from hundreds of years ago.  It’s hard to understand in places, but there’s a big part in there that talks about the properties of dreams and… death.”
 
You feel a slight chill.  “Why those?”
 
“Um, well… if I remember right, the book says that dreaming is the space between life and death.  When we dream, we are separated from ourselves, and are shown that the divide between our living and our dying is not real.  We see aspects of reality that we can’t really comprehend.”
 
“Sounds like heavy stuff.”
 
“There’s more.  They weren’t satisfied with those limits, and they weren’t satisfied with just trying to understand them.  The book is about how somepony can understand the power of dreams and death, and then… use that power.”
 
You recall the superstitious nature of humans you’ve met in your travels, the way they’d talked about death.  They would have closed their ears to this discussion out of fear, unwilling to hear more about the ancient ones and their blasphemies.  But to you, even though you still hold some of the old superstitions, your curiosity is piqued.
 
Your head is pounding.  “Is that the part that interested you?”
 
Moss Moon laughs softly.  “I actually liked the parts about medicine the most.  Anatomy, how to make healing poultices, preparing potions, those sorts of things.”  She pauses.  “But it’s definitely something I’ve thought about a lot.  And Grandmother is obsessed with it.”
 
You suddenly become acutely aware of the silence of the road.  You stop, standing with the torch in your hand.  The path stretches on ahead of you, the flickering light going from pink-orange to bloody red to darkness.  In both walls, tunnels open like mouths in front of and behind you.  You are enclosed on all sides by stone.
 
Moss Moon is looking at you, her expression worried.  “Everything all right?”
 
You squeeze your eyes shut before blinking a few times.  “Yeah.  Just tired.”
 
She moves to take out the bottle of black liquid again, but you wave her off.  “Save it.  We might need it later.”
 
The two of you proceed further up the path.  The tunnels increase in frequency, and you begin to notice that some of them were clearly not shaped by builders, but rather appear to be gouged into the rock, as if something huge had simply ground its way through the mountain.
 
You feel your vision swimming from exhaustion.  Your head aches.  You have the vague impression that something is not right.  It occurs to you that you should say something.
 
“Thanks for telling me about the Spring, and the books,” you say, not sure if you’re slurring.  “You could read them to me when we get back, if you want.”
 
Moss Moon smiles at you, though her face is a little blurry.  “I’d like that,” she says.  Her voice sounds like it’s coming from far away.
 
You turn to look down one of the tunnels to your left.  At the end of it, standing in the dark, is the shadowy shape of a pony.  It watches you silently.
 
“Just what did happen to all those ponies?” you ask.
 
You feel Moss Moon touching you.  “Anon?  What are you looking at?”
 
“The ones who lived on the other side?”
 
The ground begins to rumble, and it seems as if the whole mountain starts to groan.  You feel someone grabbing you.  “Anon, this is a big one, we have to move –”
 
In the tunnel the other pony does not move.  You lift your torch to look at it and you see its hollow eyes and bone white teeth.  You hear foals crying and the mountain tearing itself apart around you.
 
A second later you are on the ground, and the torch is sputtering a few feet away.
 
You blink, feeling strange as your thoughts return to order.  As lucidity once again seeps into you, you realize that Moss Moon is sitting on your stomach.  The mountain roars, shaking violently.  You hear a crack and feel the ground shift under you.
 
“What’s happening?”
 
“Gas!”  Moss Moon shouts.  “And an earthcrawler!  Follow me, and keep your head down!”
 
She bounds off of you and you dash after her in a crouch, picking up the torch just before it gutters out.  Almost immediately she diverts into one of the tunnels, following it as it winds down into the earth.
 
After about a minute of running, you almost bowl into her as she stops.  The mountain continues to shake.  She pulls you down to the ground and directs you to cover your head.  You can hear her praying.
 
Not knowing what else to do, you drop your torch to pull her against you and cover her with your body.  You can feel her trembling against you.  Rocks from the ceiling pelt your back, and you can feel yourself mumbling fervent words in the hope that they will ward off a cave-in that would kill you both.
 
It’s all happening so quickly.  You wonder faintly if this is a dream.  But the sturdiness of your companion, the pounding of her heart, and the quaking of the earth tell you that this is all too real.
 
“Anon, if we –”
 
“I –”
 
Then the ground splits, and you are falling, and no amount of strength can keep her in your arms.