Starlight skidded to a stop at the lip of the cave. It opened abruptly in a wall of sunlight, the river dropping out from beneath her and her ledge doing the same a few paces later. Above, below and all around stretched a sheer, vertical wall of stone, the river simply popping out of a hole in the side and falling into the distance.
Across from her, many meters away, rose a parallel wall baked gold by the afternoon sun. Starlight swallowed, hairs prickling at the sight: she was in a colossal canyon, a harsh sideways wind whipping past and nearly threatening to unbalance her. She crouched low to the ground, weathering the blasts and fluffing her coat in defense as the scale of the mountains overwhelmed her with its suddenness.
Above, the sky was blue. Her ears flicked as she watched it; this wind must have blown the clouds away. She could see trees packed all the way to the edges of the gorge, leaning perilously and in one place even forming a natural bridge across the wonder. Below, a river churned, much larger and more violent than any she had crossed before. Flowing from around a bend to her left, it rushed past her, fed by the comparatively small cave stream she had been following and surging on into the... horizon?
Starlight blinked. The left end of the canyon bent and twisted out of sight, but the right one simply vanished, ending the river in a curtain of mist and above that, a spotless blue sky. Conveniently, the ledge she stood on clung to the cliff face for a ways, allowing her to get closer.
Crawling to minimize the area of her exposed to the wind, Starlight crept forward along the narrow protrusion, hooves scraping across loose stones and pebbles that had likely fallen from above. As her eyesight adjusted to the size and depth of the canyon, she grew slightly more confident; it wasn't that deep. The water below was close enough that she could throw a reasonably-sized stone and probably hear the splash, and the cliff edge above was low enough down that if she tried to climb it and fell, she might be able to do it without breaking anything important. Not that she wanted to try, of course.
The ledge kept going, widening and narrowing in intervals as she slid cautiously along it. It rose and fell, dipping so low at one point that if she pinned her tail to the edge and dangled from it, she might be able to touch the splashing spray. All warnings of venturing too far from her supplies forgotten, the filly pressed on, determined to see what lay at the end of the canyon.
Starlight's ledge reached the end, and she saw that it wasn't just the end of the canyon - it was the end. Everything dropped away, from water to mountains to land itself in an endless expanse of green below and blue above. This was a more dramatic height change than what Starlight had seen emerging from the peak tunnels, the landscape so far below that she couldn't even make out individual trees. But trees were what there were; green intermixed with black and gray in a sharply rising and falling sea of stone and foliage that looked more like a bumpy carpet from her vantage.
On the horizon, where miles turned to inches and those into an atmospheric haze, a flat belt of clouds retreated, blown out of the mountains by the wind and sent to annoy the lands below. Aside from that, the sky was so open that it might not have existed at all. For a moment, Starlight stared upwards, before realizing she was above the sky. She pondered if this was how pegasi felt, before remembering that she had never seen one soaring overhead with even a fraction of this much height. She was on top of the world.
Finally, her eyes focused on the horizon, and she took in the most important detail of all. At the base of the waterfall where the river left the canyon, there was a massive lake, hammered into the bedrock by untold years of pressure and torrents. At the edge of the lake, a tiny ribbon of blue trailed into the forest before it was lost to the canopies... but she could still track its path by following the depressions in the landscape. And perhaps twenty or thirty miles downriver, she could see smoke.
It wasn't the thick, dark smoke of a forest fire, but a wide, compound haze caused by hundreds of controlled burns in one area. Her purple eyes shone, reflecting the pillar: that was the work of ponies. And for there to be so many ponies in one place... she was within sight of a town.
Soberly, she reminded herself that when you could see forever, something being in sight didn't count for much. Still, she had a promise from the land: if she followed the river, there would be an end. Perhaps it would be a community of ponies who wouldn't care if she never got a cutie mark!
That still left her with the question of exactly how to get there. Miles meant miles, which could mean days with no guarantee of shelter in a climate where rain could appear without warning. Even that close, one unfortunate soaking could still spell disaster. More importantly, she needed a way to lug her saddlebags and self down a cliff higher than a pegasus sky city, a drop she would have been nervous to take even if she had been a pegasus herself.
She scooted forward, examining the edge of the cliff as carefully as she could. Sosa had made a camp in that cave, and had mentioned having a boat. Any logical place to put a boat would have to be downriver of all major waterfalls, which likely meant he had climbed up this way... which could mean he had left a way back down.
Deciding to take the fast method of searching, Starlight closed her eyes, stuck her tongue out, and expanded her telekinetic aura. She wrapped it around the cliff face near her ledge, tightening it just enough to perform her newly-invented scan, and rubbed, getting a feel for the edge. Quickly, a line of thin, hard spikes protruding down the wall stuck out to her, and she blinked in realization. The contents of the first crate she had scanned must have been some sort of nails for anchoring a mountaineer to a cliff face!
Unfortunately, she was still without rope, which meant such things would be useless. And even if they were close enough together to form a ladder... she shivered mightily. Starlight wanted nothing to do with a plan like that. She poked her head out around the edge, looking at the rest of the mountainside in hopes the slope got easier elsewhere, and was rebuffed.
Groaning loudly, Starlight plopped herself down in the dust at the edge of the cliff and yelled at the sky. But it was clear that she had reached the end of the trail, and there was nothing more she could do there. So, feeling the beginnings of hunger stirring and other signs that she was beginning to tire, she got back up, turned around, and began the long ascent to return to her camp at the lake cave entrance.