‘Hide’ has the Doctor and Clara crashing a ghost hunt at Caliburn House conducted by Major Alec Palmer and Emma Grayling. Supernatural investigations are can serve as the inspiration for an adventure or the basis of a campaign.
The classic series had little time for ghosts and other elements of the supernatural. The 3rd Doctor in particular was dismissive of the reports of spectres in ‘Day Of The Daleks’. In the new series the world at large seems more accepting of the idea.
Indeed in ‘Army of Ghosts’ people accept the presence of phantoms, incorporating them into their lives. It would appear that people can more easily handle the idea of life after death than they can life beyond our planet.
Emma Grayling status as a psychic is also not questioned. The Doctor has experience with such phenomena but both Major Palmer and Clara accept her mental abilities as fact. It is clear that in the Doctor Who universe psychic abilities are a fact.
That being said ghosts usually turn out to be aliens, time travellers or psychic impressions (sometimes a combination of all three). This means that ghost hunters could be forever searching for proof of the real thing.
Ghost hunters create the perfect starting point for an adventure. By their nature they head into the unknown, placing themselves in potential danger and actually hoping to meet something unnatural. Whether they are PCs or NPCs ghost hunters are characters who can be put in a perilous situation with very little justification.
Once ghost hunters are in place you can concentrate on the meat of the story, locating ghosts. The site being haunted can vary wildly from a traditional haunted house to a deserted work place or, if you want to include a science fiction element, a space station.
You’ll want to think about the history of the location, since this will give the PCs something to research. Are there any tales that suggest an origin for the ghost? Are their any other recorded sightings?
Rumours and flat out lies can make it harder to work out what is true. This can be the first challenge for the PCs. Finding out what is real can prove vital in working out where they can find the ghost and working out what its nature is.
Tension is important during these early stages. There are many unknowns for the PCs, including whether there even is a ghost. You might slowly introduce unusual incidents that unnerve the characters (such as doors opening on their own or glass cracking) without revealing the presence of the ghost.
When the ghost does make itself known you must decide whether it poses an threat to the PCs. Will it attack them or is it only a messenger? The incorporeal nature of a ghost makes it difficult to fight but it might still be able to hurt the PCs.
Once the PCs know that there is a ghost the adventure can take two different paths. If they were only there to establish that the location was haunted they could decide that they’ve achieved their goal and leave.
Alternatively they may decide they now have to deal with the ghost, either helping it or destroying it. The question of whether this is even feasible depends on its true nature. If it is an alien it could be trying to invade or simply trapped. If it is a time traveller where are they from and what do they intend? If it is psychic impression what event does it record?
As Clara points out to the Doctor everyone is a ghost. PCs with a time machine can also view this in reverse, with every ghost being a person. Once they’ve encountered a real ghost they could go back to when they were living. It could be that the ghost is appearing because the time travellers were supposed to avert their deaths.
Palmer is an amateur and it is easy to imagine similar small groups of ghost hunters existing, investigating similar ghost stories in their local areas. Their lack of knowledge and resources can make an adventure much more scary (or amusing if they are the bumbling sort).
The advantage here is that even if they do discover something out of the ordinary the public isn’t likely to believe them so you can maintain the status quo of the campaign world. Only this plucky group of PCs will know the truth.
With Palmer’s military connections it might not be long before UNIT or Torchwood also start to pay attention to ghosts and assemble their own ghost hunting teams. This has the advantage of backing, support and more knowledge about what they are dealing with.
A campaign focusing on ghost hunting might take a ‘Scooby Doo’ approach with each adventure finding the PCs travelling to a new haunted location. You could take this a step further and have a cute animal or alien (or an alien disguised as an animal) for comic relief.
If you decide that living beings do linger after death as ghosts you might think about how they interact with the world. What would ghosts do if the place they were haunting was invaded by aliens?
You might decide to run a whole campaign where the PCs are ghosts. Immaterial and largely unseen they could secretly defend the world from beyond the grave. If invaders can’t be frightened away the ghosts could sabotage their equipment or secretly aide resistance fighters.
Having a PC become a ghost upon their death is also an alternative to creating a new character. A player can continue with the character they know, just as a phantom. It could be several adventures before their fellow PCs discover their departed companion is still with them.