Velma gets separated from her friends while exploring a haunted house when a thick fog rolls in. Before she knows it she's experiencing some real paranormal 'activity'. Being the intellectual she is, this is the perfect time to gather data but her interactions with the ghosts cause a mysterious substance to appear and soon she is covered in it. As the lights flicker on and off it changes in appearance and Velma starts to realize things are much stranger than they first appeared.