An immense cave system...

The step across the threshold was not as momentous as you expected- there was no tingle of magic or sense of gravity. The only difference was a notable drop in temperature, cool and wet, with a sudden distant roar of what you assumed was rushing water.

You found yourself standing at the lip of a expansive cave, the roof covered in a thick rolling fog, like a simulacrum of an overcast sky. The fog was lit, glowing in the same grey way a noon may look with total cloud cover, which allowed you to see the rest of the chamber. A worrying drop before you ended with a black pool of water what was fed by several trickling waterfalls of contrasting volume.

There was no obvious pathway, just a collection of rough cliff banks and spotty flat ground that you guess you could carefully climb to, using them as vertical stepping stones. Though one slip and you may find yourself tumbling down to a cold plunge into the water below. The waterfalls rushed out of several other entrances into the main chamber, cave passages to who knows where, the largest of which rumbling out of a hole on the other side of the chamber, much farther above you.

There were a few options here, exploring some easier to reach passages, or climbing up to the largest passage- the water had to be coming from somewhere. There was also the option of climbing down to the base of the chamber, you couldn't see the whole of it from your precipice. You also realized that the door you emerged from had vanished without a sound, and a new fear gripped you, the truth of your commitment now sealed.

You could only strive forward now...