Menace in the Zarek Valley - Pitch black

The adventurers resupply before going on their final mission. The baron provides food and equipment, as well some payment in advance.[1] The black uniforms have their own (possibly shady) vendor whom the adventurers visit. With all said and done, Ren takes the maps cobbled together by Zyn, the local Underdark expert, and the party leaves to get the job done.
The adventurers had some fun going down into the caves through a tall chute. Some used ropes, some used rock climbing equipment, and some fell. They then traveled underground for a couple of days, during which they forgot to eat and Ireth feinted.

At one point they were walking through the caves when suddenly a swarm of bat-like creatures descended upon them from above and then there was darkness.[2]

The notes do not go into detail, but the fight was long and hard. It's marvelous what some low-level monsters can do if the adventurers do not see them.

There was even unarmed combat, stepping on bats, and so on.

It could have been even more fun if I did not place things on the map and have the adventurers/players actually stumble around in the darkness. However, I felt it was more epic to see what their characters were mucking about. And then there's always the "I want to go right and hit that thing with my hammer." "Sure, roll for wisdom. Ah.. your characters turns left and hits Selene instead."

With the bats defeated and the darkness dispelled, the adventurers rested, even though I made sure that the ranger warned them about this being the territory of unknown predators. Suit yourselves.

[1] Including some platinum rings so that Groin could finally cast his spell.

[2] Giving the title of this session.