Vance, Mara, and Toby are scavengers, some of the few remaining people left. They're looking for supplies and received a tip that there's a largely intact building in the heart of the city. It sounds too good to be true, and sometimes the Ancients left protections in place to guard places that were especially important. With supplies running low, the three scavengers feel it's worth the risk...

SPOILERS AND BACKGROUND INFO FOLLOW:

So, the idea for this is that the scavs have stumbled upon an old "Halloween Emporium" that specialized in spooks and scares. The various machines are still running, with solar power or something similar keeping them running. Not everything fell apart and most people didn't think a Halloween warehouse was worth the trouble to loot. And the terrifying machines are still doing their job, so most of the surviving remnants want nothing to do with a haunted warehouse.