On Friday I talked about my favorite setup for the spooky adventure. Today I want to talk about how I set up that adventure, and how it has worked out well for me in the past. Consider it a suggestion on prepping a session or multi-session arc for a game, especially if looking to do something spooky.
Part 1: Choose The Setting
First you have to choose your setting. I call it the Abandoned House because it is frequently a house, but it can be anything from an office building to a military base to a sea vessel to a space ship. One of my favorite uses of this was in the Star Wars universe where the PCs were investigating a seemingly abandoned Star Destroyer. I've also used a Mansion, and most of the other suggestions above.
The type of game you're running will help inform this. It's hard to do an abandoned space ship in a D&D game - unless you are introducing aliens and ray guns to your game I suppose. At the same time, a Sci-Fi or Space Opera game may have problems with something as mundane as a mansion or office building.
Pat 2: What Happened?
You need to work backwards once you know where the adventure is taking place. What happened to the place? What is the mystery the PCs will be unraveling? Perhaps a Sith Lord let loose a plague on the ship that took out the crew. Perhaps the home now belongs to a vampire that has turned all the inhabitants into their undead servants. A disturbed cemetery has given rise to ghosts that possessed the people inside. Or maybe it is something mundane, and you just have a killer or something on the loose.
The idea is to know what caused the place to become abandoned. Have that firmly in mind, because you need to use that reason to answer the next parts.
Part 3: Dressing the Setting
What does the place look like? I find things looking normal - pristine and clean or otherwise undisturbed - does the best job of ramping up tension. Everything looking normal, but obviously not being normal because no one is there, is a great contrast. You can then sprinkle in abnormalities - a table set for a meal complete with food out on plates half eaten, a defensive position with no signs of having been used but all the ammo and non-mounted weaponry is gone. A single drop of blood, as if missed when a wall was cleaned.
Obviously you can go the other way. Aliens has melted floors and broken walls all around the colony on LV-426 and still does a good job of ramping up the tension of where people are.
Part 4: Run It Straight
Part of building tension with this is the whole lot of nothing happening. Which is funny because stuff should happen, but it should pan out to be nothing. A door closes behind the players, but it's just the wind coming from an open window. Motion trackers detect something in a sci-fi setting, but it's just someone's pet hamster. The more nothing happens, and yet there is evidence that something obviously happened, the more that tension mounts.
As the PCs get closer to the cause (deeper into the house, further into the ship, etc) the signs of things happening should be more obvious. The sense of closeness should be there. Sounds can be more ominous.
Bonus Part: Sound
If you are any good with sound, or have time to search, sound can be a wonderful addition to this. A soundtrack of eery/ominous instrumental music, or pre-recorded sounds of an old creaky house from something like Syrinscape can do a lot to set the mood. We trigger a lot as humans off of sound, and having something playing in the background can really add to a session like this. It's not the end of the world if you don't have it, but if you do...it can be amazing.
Part 5: Discovery
Eventually the PCs are going to have to find what happened and face that evil. This can either ramp the tension up as things go from the unknown to a big fight or being hunted, or it can break the tension as the mystery is solved. Horror movies have a long standing tradition of just being less scary when the killer is on screen, and more than a few movies have been criticized saying they should have kept the monster off screen. Others though - like Alien - have done well with glimpses of the monster and a change in tension from the unknown to the unstoppable or from the unknown to the fight for survival.