I am trapping my players, I need help making it not boring

[Apocallama]

TL;DR I am gonna trap my players in a building with a bunch of NPCs and need help coming up with plot points.

My campaign is based heavily on the demon goddess Lamashtu slowly taking over the world by possessing people in the middle of a war. These people carry out deeds in the name of lamashtu but have been manipulating the players and other people into thinking it is helping the war effort/ their families/ their town etc. One of these possessed people was a player (agreed to be possessed from the beginning, the story was mostly based off of that), and one PC the party had been doing dealings with for a while.

I have been trying to plan a session where the players are trapped inside a building in the main city with characters that they have met along the way, and induce enough paranoia into them and the NPCs the run a sort of Bottle Episode type RP session. By some force, whether some sort of weather condition is keeping them inside (tornado or typhoon or something) or maybe a monster is outside they are sure they can't beat (Maybe the session will be around gathering resources in the town to kill the monster?) One of the NPCs will be a demon, i am planning on a racist character they have had dealings with be there, a heroic character that they have made friends with be there, a kid they basically adopted out of an underground marbles ring, an NPC trader whose life they ruined by giving him a card from the deck of many things without him realising, and a few more.

I am confident that my players can handle such an RP heavy session, i am just unsure of how to add enough plot points to the session to keep my players occupied. Does anyone have any suggestions? Is this too ambitious?

[Man_Over_Game]

TL;DR I am gonna trap my players in a building with a bunch of NPCs and need help coming up with plot points.

My campaign is based heavily on the demon goddess Lamashtu slowly taking over the world by possessing people in the middle of a war. These people carry out deeds in the name of lamashtu but have been manipulating the players and other people into thinking it is helping the war effort/ their families/ their town etc. One of these possessed people was a player (agreed to be possessed from the beginning, the story was mostly based off of that), and one PC the party had been doing dealings with for a while.

I have been trying to plan a session where the players are trapped inside a building in the main city with characters that they have met along the way, and induce enough paranoia into them and the NPCs the run a sort of Bottle Episode type RP session. By some force, whether some sort of weather condition is keeping them inside (tornado or typhoon or something) or maybe a monster is outside they are sure they can't beat (Maybe the session will be around gathering resources in the town to kill the monster?) One of the NPCs will be a demon, i am planning on a racist character they have had dealings with be there, a heroic character that they have made friends with be there, a kid they basically adopted out of an underground marbles ring, an NPC trader whose life they ruined by giving him a card from the deck of many things without him realising, and a few more.

I am confident that my players can handle such an RP heavy session, i am just unsure of how to add enough plot points to the session to keep my players occupied. Does anyone have any suggestions? Is this too ambitious?

I'm just not sure if DnD 5e is a good system for this kind of scenario. It doesn't do social environments very well, especially not ones that don't involve some sort of espionage.

What I'd do is have each person have some sort of "Stress Threshhold", and the actions the players can provide (keeping people happy, distracted, agreeable) will reduce the overall stress of the group. As stress surpasses the Stress Threshold of that character, the character will lash out, do crazy things, or afflict the group with more stress. Maybe someone wants to go out into the storm anyway, or maybe several people in the group hate one another. People will start to go stir crazy. The Players can fix a lot of problems, but they can't fix them all, and they might have to resort to violence (or the promise of it) to keep the peace.

Using Dwarf Fortress as my example, the goal is to avoid a "Tantrum Spiral".

[strangebloke]

Not at all.

Lead off with something right away to set up the "whodunnit". Maybe the party cleric gets a vision. Maybe someone's been sacrificed.

Then, just create a bio for each character. List what things are going to be suspicious about each one (this one had no memory of the last two hours, that one refuses to talk, this guy just seems naturally sympathetic to the demons ) as well as a bunch of random details. What they were doing that day, etc etc. Make them lie about some things

Make a dungeon where each of the suspects has a room in. The players can investigate to learn a whole bunch.

Then, make the twist. Something happens that changes how they view the answers from the interview. One of the players loses some memories, maybe, which makes them reevaluate the guy who had amnesia.

Then, something forces their hand. Maybe the lock-in is expiring and they need to make a decision. Maybe they find the special ritual that will exorcise the demon, but they can know cast it once.