High Ledge

The crack narrows to a tight squeeze. You need to suck in your gut to shimmy to the other side. Once you do, you step out onto a narrow ledge overlooking a huge, open cavern. Occasional cracks in the ceiling let a faint light in, lighting a vast underground lake. You must be hundreds of feet above the still, dark water.

It takes you a moment to notice, but you're not alone up here! A figure sits near the edge. They are dressed in a black cloak and are holding a long fishing rod. Their line runs all the way down to the water below. They don't seem to have noticed you yet.

At the far end of this little ledge, you see another tunnel. It looks neatly formed, almost perfectly square. Perhaps it's artifical? You can't see what lays through the opening.