The Prep Pool - How to be Ready for Anything

Imagine sitting down at the table for a session as a game master in a sandbox or hexcrawl campaign, being fully confident that whatever the players decide to do, you will be able to handle it. No matter in which random direction they head - figuratively or geographically - you'll have prepared content ready for them. To your players, you will seem like you are always ready for anything.

Sound implausible? Well, not quite - it can be done. There is some work involved, but probably less than one would imagine.

The problem

When running a roleplaying game, there is always a risk that the players decide that they're going to do the unexpected - head off into the wilderness in a random direction, accost a random NPC in the street demanding answers, or demand to visit the local tavern to get into a fight fueled by liquid courage.

This poses a problem for the game master. How can you possibly be ready for anything the players might do? How can you have interesting locations prepped in all directions, and how can they all be prepped with engaging NPCs in advance? A lot of game masters are very good at improvising, but I am not; such skill comes with experience, something which I myself have yet to accumulate a sufficient amount of.

The solution

The good news is - you don't have to have everything prepped in advance. The solution to all of these problems is to have one or a few of each (NPC, location, dungeon, etc) prepped. But instead of putting them in a predefined spot, you put them in the Prep Pool, ready to be grabbed on the fly in a session and placed where they are needed. This is the key - things that you prep and put into the Prep Pool should be generic enough that it can be put basically anywhere, geographically speaking.

Make sure you "store" all the contents of your Prep Pool in a way which makes it quick and easy to find them on the fly during a session. If you keep your notes digitally, it could be a good idea to have a document called Prep Pool which contains all your Prep Pool contents, or direct links to each item.

After each session where you've used something from the Prep Pool, you replace it with new content to make sure you're ready for the next session - more on that later in this article.

Reskinning

When you prepare contents for your Prep Pool, try to make it "reskinnable" - that is, make it easy to change on the fly as needed. A temple from your Prep Pool can be described as you intended when you created it, but you can also decide in the moment to describe it as being "overgrown and empty" instead of as being "well cared for, and full of people." Thus, you have reskinned it on the fly to look abandoned, because you ended up needing it deep in the jungle rather than in the city context you envisioned when you prepped it.

In this context, reskinning is simply a change to how you describe something. You don't have to alter the actual visual appearance of a map you're showing the players, for example; that can't be done on the fly for obvious reasons.

What should one put in the Prep Pool?

It is up to you as the game master to decide what categories of content you want in your prep pool. What follows is the categories I use for my fantasy world, along with some notes on each.

NPCs

NPCs are the bread and butter of any TTRPG world. If you ask players what they remember the most after they've finished a campaign, they will often bring up NPCs that they liked. So don't underestimate the importance of having memorable NPCs.

Make a few NPCs which are interesting yet largely unconnected to the world, making it so that you can logically place them wherever they are needed. A queen is probably a bad example, as she is unlikely to be suitable for many situations. But remember that NPCs don't always have to be encountered at their place of work. It would not be strange to encounter a tailor in a forest - people are not typically chained to their place of work, and it makes sense for someone you meet in the forest to have a day job.

You can, of course, make the NPCs yourself, or get them from a suitable source such as a Monster Manual for the game you're playing.

If you want to make your own, you could refer to The 4D Method of NPC Creation for a relatively quick method of creating NPCs. And if you want something more involved, which randomly generates both appearance and personality, you could have a look at my full NPC Generator.

A barkeep which can also double as merchant is a good pick. PCs often interact with them.
A town guard which can also double as a soldier is another reasonable choice. PCs often end up in contact with guards, whether they're on the right side of the law or not.
A traveler which can double as a generic commoner or farmer is also a good addition to your Prep Pool. They can be encountered while traveling, as a prisoner in a dungeon, or as a low level ruffian as long as you give them a dagger or other inexpensive weapon. They can also serve as a victim of a crime, and so on.
A bandit is also a good choice. Give them some leather armor, a sword, and a shortbow or whatever you deem appropriate for your setting.

If you keep these four in your initial Prep Pool, you will likely have enough to keep the PCs busy until the end of the session even if they do the unexpected.

Encounters

Combat and other encounters are common in most roleplaying games, so keeping a few in the Prep Pool is probably a good idea.

A bandit ambush or monster attack, optionally also with an appropriate battle map if you use them.
A social interaction encounter can also be interesting. Perhaps an argument between two farmers about grazing rights, or a pregnant traveler urgently needs help as her water breaks?

Settlements

Settlements are also common places for PCs to come across or visit.

A village is often useful. Make sure it has a name and at least a few interesting locations and/or shops. It should be possible to reskin the village as abandoned, or even ruined - or perhaps under attack or overrun by goblins?

Dungeons

Dungeons are a staple of all TTRPGs, at least in most of the fantasy ones. The Five Room Dungeon is a well-known method for creating interesting dungeons. Note that such a dungeon can in fact have more than just five rooms; the point is that the dungeon should have five specific types of rooms (entrance, puzzle, trick, climax, and reward), among others.

A crypt is a good choice for your Prep Pool. A long-forgotten crypt can be stumbled upon (and literally fallen into) basically anywhere - even in the middle of a sprawling city.

Other locations

There are many types of locations you can have in your world, and your imagination (or available random tables!) truly are the only limits.

A bandit camp goes well with the idea of having bandits as NPCs in your Prep Pool. If needed, it can easily be reskinned to a generic travelers' camp, hunting camp, or logging camp.
A haunted house is one of my personal favorites. This one could be a lot of work, as it probably should include a way of dealing with the ghost either by destroying it, or helping it with whatever unfinished business keeps it trapped in this world. If you prepare it as a mansion where people live within a city, you can reskin it as an abandoned house in the wilderness.
A cottage with an orchard can be a nice change of pace from all the conflicts of a TTRPG world. Perhaps the owner needs to make some upgrades, and is looking for someone who is willing to invest in this enterprise?

Rewards

All players want rewards, and it's always a good idea to have a few interesting ones up your sleeve (read: Prep Pool).

Magical weapons are always popular, especially if they come with some history. Who made it, and why? What was it used for? And what happened with it - why is it no longer (buried with) the original owner?
Other magical items will also be appreciated by the players. They can range from useful to cosmetic.
Gold and an improved reputation don't technically go into the formal Prep Pool, because they doesn't actually need to be prepared - these types of rewards you can just improvise when appropriate.

Quests or Situations

A lot of times you can improvise quests or situations for the PCs to deal with, using the contents of your Prep Pool. Have an NPC from the Prep Pool tell the party that a reward from the Prep Pool is rumored to be hidden in a dungeon from the Prep Pool, or something along those lines. But if you want, you can also have entire quests - you can think of them as one-shots, if you like - ready to go in your Prep Pool.

When you have used content from the Prep Pool

Once something from the Prep Pool has been used in the game, you should do the following:

Remove it from the Prep Pool. This doesn't mean that it can't be reused though; an NPC from the Prep Pool doesn't cease to exist after the party has met them.
Make a note of where it was used, on your map if appropriate (read: if it is a location as opposed to an NPC or reward, etc). After all, it makes sense for a cave to still be there the next time the party visits the same place.
If it was reskinned, make a note of that too so you don't accidentally describe a village as "bustling with life and activity" if you had reskinned it as "abandoned" last time the party was there.
Refill the Prep Pool with new content, to make sure it's ready for the next session.

This means that every time the party encounters a location from your Prep Pool, your world permanently (more or less) changes - that haunted house you had in your Prep Pool now permanently resides wherever the party found it.

Criticism of the Prep Pool

Some would say that the content of a Prep Pool is inherently generic, and by its nature of being largely but intentionally unconnected to the rest of the world in order to be "pluginable" anywhere, it is therefore boring. A generic bandit ambush or random unrelated dungeon will not bring the plot forward. This is a valid criticism of the Prep Pool concept. It is better to let the PCs interact with specifically prepped contents which relates to the matter at hand, whatever it may be.

But think of it this way - the Prep Pool is the game master's safety net for when the players decide to go off the predicted path. It is an alternative to saying:

You approach the job board at the town square to find your next quest, but you are stopped by an otherworldly purple shimmering force field. As you examine it more closely, you find a small label on the force field which says "You have reached the limits of the GM's prep. Please come back later."

This is something I've had to do a few times, because I didn't have a Prep Pool at the time. You can either decide that this is fine, and it is! It's totally valid to say "Sorry guys, but I haven't prepped that yet. Can you do something else in the mean time, and I'll prep that for next session?". But the Prep Pool is an alternative if you don't want to have to say that.

But what about the infamous Quantum Ogre?

The well-known blog post On How an Illusion Can Rob Your Game of Fun brings up the case of the "Quantum Ogre". For those who are not familiar, in short the blog post is about how lack of player agency ruins the fun. If the game master has decided that the players will encounter an ogre today, and then places that ogre in front of wherever the players decide to go, then the players' choice of where to go becomes meaningless. The game master has decided that they will encounter the ogre, and no amount of skill on the players' or PCs' side will change that. The ogre is utterly undetectable until initiative is rolled, and there is no way for the PCs to avoid the encounter. This is a valid criticism of that style of game mastering.

So can't that criticism be levied against the Prep Pool? If the NPC from the Prep Pool is the same no matter where the PCs are, does that not in fact make the NPC "Quantum?"

Well, yes - that's true if the game master places things from the Prep Pool without thought. So, don't do that. Instead, choose appropriate content from the Prep Pool and reskin it if necessary to suit the environment in question. This is why it is preferable to have easily reskinnable and multiples of each type of content in the Prep Pool. If the only NPC you have is a king, and the party encounters him in the sewers, then things might seem a bit… odd.

Stalling

You can also think of the Prep Pool as a way to stall the PCs when they do something unexpected. "Oh, they want to do more dungeons? Well, I do have that dungeon I prepped a while ago and put in the Prep Pool, I can put that right next to them and let them do that today. Then I can prep a second level for it for the next session." This is absolutely a valid strategy.

In conclusion

If you're like me - a game master who prefers the psychological safety of knowing that you will be able to keep the players busy until the end of the session, pretty much no matter what they do - then the Prep Pool might be for you. In a pinch, its content can also be used if you for some reason didn't have time to prep for a session. Just grab a quest from your Prep Pool, and you're done. And if they choose not to bite on that particular quest hook? Well, you've still got the rest of the contents of your Prep Pool to fall back on.

But remember - you must always be kind to yourself as a game master. Prepping is a lot of work. If you do not feel ready to run a session, then there is no shame in saying so to the players. If you manage to do so well in advance of the planned session time, perhaps one of the players can run a one-shot for you and the other players instead?