The scenerio I have in mind is thus:
A drow raiding/scouting party is travelling through the Underdark, where they're ambushed by deep gnomes or dwarves. Vicious battle, yada yada, but the drow in all their glorious racial superiority are winning.
So the ambushers collapse the tunnel.
Enter whatever characters we choose to play, being the only survivors. They have to find a way out and escape the tunnel, all the while knowing that their enemies are probably going to come looking for survivors at any moment. Perhaps they do, perhaps we actually stumble upon the enemy city....where ever we decide to go with it.
Whatever character concepts we dream up could make for a myriad of interesting games. A priestess and a drow warrior? Two warriors or priestesses from rival houses? Or rival siblings? It could be an excellent chance to off your older sibling, but it might take both characters to make it out alive in the first place. I'm alright with romance developing or not, so long as the character development is good :)