The party found themselves captured after being sedated by a Drow slaver ambush. When they woke up they were imprisoned along with a band of different creatures, varying from an intelligent mushroom creature, to a female dwarf. Also, in the cell, they came across the monk Kharazim. Unwilling to speak at first, he eventually befriended the party.
After many days of captivity, they managed to escape, but it was not an easy task. Many handful of drow, including some elite warriors, tried to stop them. When the party realized they they were outmatched and outnumbered, they made a desperate escape by jumping down from the ledges of a city, down to a giant spiderweb below.
And where there is a web, there are spiders. And when that web is gigantic, you can place your bet on that the spiders are gigantic aswell. A few of the fellow prisoners were unable to tear themselves free of the web, and were killed by spiders, the size of horses. The rest of the party managed to jump down in the waters below.
They quickly moved on to get away from their captors. As they traveled, they had to stop to gather food and water, just to survive the harsh climate down in the Underdark. All while they were certain the Drow Scouts vere mere hours away from catching them again.