The ghost of a teenager seeks revenge against a snobbish family. Your job is to scare them out of their house(s). They can't see you, so your only means of scaring them is by possessing various objects throughout the household. For example, possessing a piece of furniture would cause something to fly out from it, and possessing an object would make it come alive in some way or another. You need to act quickly because you have something called "ecto" which acts as the fuel that allows you to roam the real world. You're awarded more ecto each time a family member exits the room. The more scares you did, the more ecto you gain. Losing all ecto sends you to the underworld where you have to regain your ecto to full capacity in order to go back into the real world.
Description from MobyGames