In their bid to defeat the Darkness once and for all, Sam Winchester formulated a plan to use souls to build a destructive bomb. Unsure of where to gather enough souls, Dean suggested this sanatorium. The boys entered the place and began hunting the souls down. Once they had collected everyone, Billie the Reaper came and took notice of their actions. She decided to help them create their bomb. Since the bomb was ultimately deactivated, it is unclear what happened to the souls who once haunted this place.