The fic I'm looking for has Giles sending Spike and Buffy going to some house that they heard had a nest of vampires, or something like that. Once they step inside Spike falls through the floor and a piece of wood goes through his chest just barely missing his heart. Buffy helps him back upstairs and then the front door to the house shuts and locks them in. They're in there for awhile when Buffy and Spike start having sexual fantasies about one another, but Spike's turn darker when he goes as far as shifting into his demon and he bites and kills her...in his fantasy. They soon start to realize that the house is doing something to them and Spike is unable to control his demon.
This isn't the first time I've lost this fic but I'd like to find it again. Hope someone can help. | 
