Into the Crypts of Tressendar Manor
The tunnel turns out to be rather narrow, wide enough for one person to go through fairly easily. The walls of the tunnel are just ordinary dirt for the first 40 feet before changing into rough-cut stone which goes on for another 60 feet.
After 60 feet, though, you need a light source, but Mithra quickly realizes that there is a dim light up ahead. It's enough to follow the tunnel, but not enough to see well.
Reaching the end of the tunnel, it appears to open up into an irregular cavern that stretches away from you that's around 30 feet wide and maybe 100 feet long. A 10-foot wide, 20-foot deep crevasse runs through the length of the cavern in the middle of floor, just to the right of the tunnel's exit.
A cold breeze wafts through the cavern, carrying a faint smell of decaying flesh. You can see two stone columns holding up the 20-foot ceiling. One is nearby on this side of the crevasse, the other is farther away on the opposite side of the crevasse.
There are also two arched wooden bridges over the crevasse, and the cavern is lit by two torches. One torch is in a niche 15 feet to the left, and the other is near the other end of the cavern.
Two other openings can be seen--one out of the left side of the cavern about 5 feet along that wall, and one out of the right side of the cavern but on the other side of the crevasse.
There might also be another exit at the far end of the cavern; it's hard to tell from here, partly because the stone column on the other side of the crevasse is blocking the view.