What lies below?

After a night's rest we decided to follow Brunen's party into the cave in the crevasse. We did note that it was obvious that Brunen's group had left within the last few weeks. After discussing how best to supply ourselves with food & water (magic works best), we headed into the cave. We almost immediately came to a T-junction. A quick check found signs they had gone to the right. We headed that way. A bit later we came to a fork. We found no signs this time, but we chose to go right. After a few more hours & many twists and turns we were attacked from above by a creature with many tentacles. Everyone but Vadranna was quickly grabbed! Sir Arathur was unable to identify it. After some thought, Aaron was able to identify it as an Aboleth. After hacking off most of it's tentacles we defeated the creature. We did not find any signs of the group we were following. Sir Arathur even cut the creature open to search it's stomach. Since we found no sign of them, we decided to head back to the last fork and take the other path. We camped for the night to relieve some enfeebled conditions we were all experiencing from this creature.
The next morning we backtracked about an hour and took the other fork. After a bit more travel entered a cavern with with a river running through it. We were somewhat surprised to find a worked stone bridge over the river with several stone structures on the far side. As we got closer we found there were 2 giant stone statues of Dwarves with an entrance between them. Sir Arathur noticed that there were several sets of footprints leading in through the door. There were some smaller ones that seemed to indicate perhaps Halfling footprints. As we moved forward we could see that door was open. We entered, finding a worked stone hallway that appeared very clean. There were no signs of dust anywhere. We found several rooms with closed doors off of them. After finding no open doors, we decided to go through the one where we could hear some sort of scraping on stone noises. Jemaig opened the door, only to find 2 ghostly creatures inside. Before he could react the smaller of the 2 floated forward to attack, quickly followed by the larger one! He then struck back at the small one, before stepping back to allow room for the creature to step into the group of heroes. Would it be dumb enough to do so? Vadranna was able to identify the creature as a Wraith. Sir Arathur was able to identify the larger one as a Dread Wraith. We thought we were in pretty good shape... until 2 more Wraiths rolled up on Aaron from elsewhere in the complex! We quickly dropped 2 of them, but the Dread Wraith and 1 of the regular ones became a serious pain, dropping various party members and draining most of us a bunch. After a somewhat protracted fight we ended up running away. To our great sorrow, we lost Vadranna to the Wraiths. In a selfless act, Jemaig stood against the Dread Wraith while the rest of us ran. To our surprise, he came running after us shortly after the rest of us got to safety. We decided we should rest for the day and head back inside the next day to, hopefully, finish off the Wraith. Maybe Wraiths, if Vadranna had risen as one as well.