The party encounters the ghosts of Gustav and Elizabeth Durst in the basement. Leveraging their experience being the Durst children, Grey and Tom learn that the "grown up parties" the Dursts held were actually meetings of a cult that worships Barovia's immortal lord: Strahd von Zarovich. Elsewhere in the basement, the party finds a crude statue of Strahd holding a glass orb filled with smoke, one eerily similar to one Grey already owns.
The cult members now exist only as spirits and shades, and they demand a sacrifice. When the party doesn't oblige, the cult helps them along by animating a massive corpse golem named Lorgoth the Decayer. Lorgoth quickly engulfs Brenna, reducing her to 0 hit points instantly. However, before the golem can get her to the altar to complete the sacrifice, Brenna rolls a 20 on her death save, waking up inside the shambling mound with 1 hit point. She casts thunderwave, escaping Lorgoth's body and shoving it off the altar. Everyone is suitably pumped about all this as they flee the house, which manifests ghostly scythes, swarms of rats, and noxious fumes in a futile attempt to kill the party.
The party escapes the house at midday of their first full day in Barovia.