To start with, in your setting, what do the dead know and what limitations, freedoms or powers do they have? For another thing, does your character have any influence or control over them?
For a few examples: Are ghosts bound to a particular area, or are they free to roam? Can ghosts lie to your character? What about manipulative use of the truth? Can they report on the afterlife, or at least undeath? Are their perceptions expanded or reduced from those of the living? How much do they remember of their lives? Are they privy to information not available to mortals? Can they read minds? Could she get a ghost to spy on someone for her, following them about their business? Can ghosts possess people?
My Games & Writing
The thing with the red gold crown.
Where the guy hides his spare key? What is the combination to the safe? Does the guy take medicine and where is his pill bottle?
Use them as invisible sentries. Use them to scope out an area before preceding.
It comes. The corrupter comes. Don't let it touch the tower lest all reality crumble.
Impudent Upstart
The most profitable questions would probably be those that people ask mediums to ask their dead loved ones in the real world. What is it like where you are? Are you happy? Do you know we loved you? Stuff that helps bereaved ones find closure.
On the shadier side of things, my first thought was that killing a spy is now no longer a sure-fire way of keeping your information secret. That, or contacting a disgruntled and deceased former employee of a secretive organization would probably unearth lots of stuff people would rather have kept in the dark.
Depending on how old these ghosts can be they could also solve some even older mysteries. Perhaps learn the truth about a historical event shrouded in myth from somebody who was actually there? Or, they could ask dead artists how their unfinished work would have ended. Or, if the ghosts are especially cognizant they could even actually ask somebody who was a genius in their field for advice on a modern problem (assuming their knowledge of the field hasn't become hopelessly outdated in the intervening years of course).
Nobody wants to be a pawn in the game of life. What they don't realize is the game of life is Minesweeper.
Another question occurs to me: is there anything in the setting that might masquerade as a ghost, for whatever reason? (Such as an evil spirit attempting to lead the heroes away from something that it doesn't want uncovered.)
edited 11th Oct '13 4:28:45 PM by ArsThaumaturgis
My Games & Writing
For a superhero setting, one of my characters can see and talk to ghosts. Initially, I had her as a possible side character on a Super Team, filling the role of Dark Magical Girl or something similar. Only recently did I realize that with the proper use of her powers, she might be one of the most powerful members, maybe even the leader.
Understand that in this setting, most superpowers are pretty low key, with more emphasis on Non-Powered Costumed Hero types and effective use of minor powers by regular folks than godlike supermen. With the ability to talk to ghosts, you could learn secrets others would never know. Where the bodies are buried, where the loot is stashed, where the boss hides his liquor in the office. You could use this knowledge to find hidden treasures directly, or to solve cold cases for the reward money, or have blackmail material against people in high positions of power. Basically, I see her power very easily lending itself to the occupation of Knowledge Broker or a similar dealer in secrets.
So what do you ask the dead? What are some more things she could learn?
Machines were mice and men were lions once upon a time, but now that it's the opposite it's twice upon a time. - Moondog