After entering the Basement, the party quickly discovers it is some sort of crypt. They are attacked by a number of creatures as they explore and gain some items, A grick from an alcove in the dining area, some ghouls in a hallway, and a mimic disguised as a door.
After resting, they find some ghasts in a bedroom which they quickly defeat, and gain some useful equipment from the chest at the foot of the bed.
Going deeper into the basement, they hear chanting, an eerie sign of what lies ahead. They discover a prison area where they find cloaks with the symbol of Vecna. This suggests that the Durst family were followers of Vecna and hosted some of the cult in this underground area. As they enter an alter room, they are drawn to the alter where cultists appear around them, the Symbol of Vecna tatooed on the backs of their hands and call for a sacrafice.
Refusing, the cult releases an undead shambling mound on the party. Unfortunately, Dior is engulfed and unable to be saved, perishing during the fight. After being defeated, the whole structure tries to kill the party as if it has a mind of it's own. Luckily the party escapes and the mists that first drew them to the Death House deposit them near the gates of Neverwinter.