Tonight I had another cool idea, perhaps for a comic. A woman is host to the spirits of three dead people and can hear them in her head. But she can't see them. They basically inhabit her brain.
So the first question is, is she simply crazy. And she might be because she has a persistent and unexplained meningitis for which she seeks ongoing treatment, always with the hope/fear that it will stop the voices. Also, insurance and all that would eventually be a problem.
The first spirit is, she believes, Aristotle. He is a genius and a polymath but speaks in ancient Greek, which she starts to study in order to understand him.
the second voice is a deceased comedian or con man, a complete manic personality. While he has great insight into people, it often comes wrapped in insults, and he's a very bad influence -- think Mark Twain in his dark period or Robin Williams on a bender.
The third is her dead grandmother, whom she remembers from childhood but never got to know very well. This leads to complications in her love life. Imagine how hard it would be to have sex knowing that your grandmother was in fact watching and doing her best to bite her lip.
I don't really have a plot, although obviously at first there will be quite a bit research into how this has happened and how it might be ended while at the same time dealing with the sudden addition of three completely incompatible people. Life falls apart and all that.
For example, her boyfriend says bye-bye after she suddenly stops having sex with him.
So the question is, has it been done before?