Whenever I'm planning a session for my campaign I tend to prepare a very strict plot. It makes me feel comfortable, and though you can never feel entirely ready; it makes me feel somewhat ready to play when I have a plan.

If the players go off the pre-planned path it really messes me up.

Is there a specific planning process or formula that most DMs use in planning a session? Put another way: is there a way to plan a session, that is flexible to what the players do?

Is there a formula (or something similar) that most DMs use?


5 Answers 5


Don’t prep plots, prep situations.

I will only be parroting that excellent post by The Alexandrian.

In short, you should not prepare a sequence of events that your players should follow, but you should prepare the environment, the actors, what they are planning to do and how, and allow the players to react to the NPC actions and world events, and in turn allow your NPCs and your world to react to the players.

Here’s an analogy: Situation-based design is like handing the players a map and then saying “figure out where you’re going”. Plot-based design, on the other hand, is like handing the players a map on which a specific route has been marked with invisible ink… and then requiring them to follow that invisible path.

Look at the article, it raises a specific comparison of how the two types of preparation compare, argues that situation-based prep is not significantly more work than plot-based prep, and links to other GM guidance items to help in designing robust scenarios.

  • \$\begingroup\$ Great answer. I would add that this is actually how the (in my opinion) well written campaigns published by WotC approach the "preparation". If you read, e.g., Curse of Strahd, it will tell you where each NPC is, how they behave, but will never tell you "If the PCs do X, you do Y". I do the same in my campaigns, although I never understood it in a systematic way (it just felt natural to do this way). \$\endgroup\$
    – HellSaint
    Jun 18, 2020 at 16:05

In my experience, the best way to be flexible is to plan less, not more.

The further ahead you plan, the more time and mental capacity you devote to plans that may never come to fruition and the more you'll be frustrated when the players go off the rails you planned. Instead, IME the trick is to plan just enough to get the adventure moving and wing all the rest.

What you do want to plan is:

  1. A general theme for your game.
  2. An initial situation, with some hooks to get the players moving — preferentially, but not necessarily, in the general direction you want them to go.
  3. At least one potentially satisfying ending to the game that you can steer your players towards if needed. You'll want to plan this in advance so that you don't end up running out of ideas and just having to end the game on an anticlimax when the players run out of things to do. But be prepared to revise or totally change this ending if the players end up taking the plot in a different direction.
  4. Optionally, one or two reusable set pieces (e.g. epic fights, plot twists, etc.) that you can throw in your players' way if things start to get boring. Don't spend too much time planning these, since you might end up never using them, but it can be handy to have a couple of these in your back pocket. Ideally, they should be generic enough that you can quickly adapt them to whatever circumstances your players find themselves in.

With some luck, those should be enough to get the adventure moving and your players to set goals for their characters and start making their own plans. Once they start doing that, just roll with whatever they come up with. Ideally, your players will take care of at least half of the idea generation by asking questions and deciding where to go and what to do; you'll just need to embrace those ideas and make them part of the world you're building.

Or, if your players ever run out of ideas, give them a subtle (or not so subtle, as the situation demands) push towards one of your initial plans — or towards whatever new plot hooks you may have come up with during the game. Or just hit them with a set piece event, have fun fighting some monsters or whatever it involves, call it a night and come up with a couple of new ideas and plot hooks for the next session, just in case your players don't.


I don't think there is something 'most' DMs use.

But there is something I've done with this. I very much know that my players, and myself when I'm a player, do unexpected things.

The way I generally approach sessions with my homebrew campaign/sessions is to work up a general plot that I'm telling. I'll prepare some encounters that are in specific places that I think they'll go, and have some other encounters ready that I can insert in other areas if the players do something vastly different.

When the session starts, I've got my 'kit' of potential encounters and the story that I'm trying to tell. But the players tell their own stories at times, and I also need to be ready to improvise both in story and in encounters. My 'extra' encounters can cover that, and they can be ready to go across multiple sessions (with some changes depending on circumstance and potentially level), but they're in my toolbox.


Mostly, though, this really focuses on needing to be ready to improvise. Remember that you are telling a primary story, but all of your players are both part of that story as well as writing their own. Work with them, let them do what they want, and do your best to improvise.

You also shouldn't be afraid to end a session early if they've made a hard left you didn't prepare for. It's okay to hit the pause so you can reset your plans and get things going again.

Going with the flow

Additionally, let the characters change the directions your plot was going in. Paths that they 'close' don't need to be negative. You can turn 'mistakes' into interesting new plot hooks. Be flexible in your own story so that the group story succeeds.

  • \$\begingroup\$ @TaylorSpaulding While I understand the urge to thank good answers, especially ones given quickly and satisfying, the comment section should be used for comments that improve the answer, not for "thank you" comments. Instead, you can thank the answer by upvoting it, if you think it helped you. \$\endgroup\$
    – HellSaint
    Jun 18, 2020 at 16:08

Two reasonable popular methods, which can also be combined:


You draw a map and place different adventure locations therein. Prepare random encounter tables. Have lots of rumours and other sources of knowledge available. Players can, by using the information, decide where to go and what to do.

Sandbox can be prepared all at once or a piece at a time. Some people even like buying a prepared one. There is lots of information on running a sandbox campaign available.

Non-player characters with agendas in a dynamic situation

Here, you prepare influential non-player characters - the queen, the dragon in the woods, the hobgoblin warlord, the high priestess - and decide what each is trying to accomplish and what resources they have. The queen wants to annex the hobgoblin lands, the dragons loves the priestess and lives between the kingdom and the hobgoblins, the priestess has seen a particular vision, etc.

The key is that all of them want the players characters to help them. Adventures are created when the player characters ally with someone or turn against someone.

For bonus points, have the player characters be some of the influential characters. This is easiest to accomplish if the campaign and the player characters are designed together, or if the characters are built with knowledge of the existing relationship map, or if the relationship map is built around the player characters.

Relevant key words for finding out more are "fish tank" and "relationship map".

Timelines (a comment by Matthieu M.)

You can also prepare a timeline for each NPC. Unless countered, the hobgoblin will have dug access to the artifact in 3 weeks, accidentally released the lich by opening the artifact in 1 week, been converted to undead, along with half its command in another week, etc... You can even identify some specific divergence points -- do they acquire this scroll they need, or not. Of course, players will wreck the plans, but you have time between sessions to adjust the goals/timelines in response to the players' actions.

General considerations

All of these approaches give players plenty of freedom (the possibility to do so is what makes roleplaying a different medium from computer games and books etc.). A game mastered used to tight plots might ask: What if they need to save the world, but choose to do something else?

The solution is simple: If the future of the world is what is at stake and the players choose not to save it, or fail at their task, the world goes boom. That this is genuinely possible makes the quest a lot more interesting and engaging; there are actual stakes.

And there are plenty of post-apocalyptic games and game worlds available, in case you want to continue the game after the world ends.

The alternative is to not have so big stakes in play.

  • 1
    \$\begingroup\$ Related to NPC with an agenda, you can also prepare a timeline for each NPC. Unless countered, the hobgoblin will have dug access to the artifact in 3 weeks, accidentally released the lich by opening the artifact in 1 week, been converted to undead, along with half its command in another week, etc... You can even identify some specific divergence points -- do they acquire this scroll they need, or not. Of course, players will wreck the plans, but you have time between sessions to adjust the goals/timelines in response to the players' actions. \$\endgroup\$ May 5, 2020 at 8:52
  • \$\begingroup\$ IMO the only real problems occur when you give the party time-limited options. It is extremely hard to have an open world and a plot prepared for them when "you need to save the world" has a timer of a week and they don't feel ready to take it on so they avoid it. moving the plot point or having some other adventuring party take care of it only works so many times before saving the world feels more like a saturday sale for pudding. \$\endgroup\$
    – IT Alex
    May 5, 2020 at 13:09
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    \$\begingroup\$ @MatthieuM. Thanks, edited into the answer with attribution. \$\endgroup\$
    – Tommi
    May 5, 2020 at 13:18
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    \$\begingroup\$ @ITAlex I added a section discussing this. \$\endgroup\$
    – Tommi
    May 5, 2020 at 13:18
  • \$\begingroup\$ Yes that is definitely true! Thank You! \$\endgroup\$ May 5, 2020 at 13:36

Grab-bag of prepared resources

I find that flexibility and improvisation is assisted by having a reasonable collection of prepared resources from which you can pick when needed.

By resources I mean bits and piecies of remixable contant:

  • Details for generic environments
  • NPCs
  • Plot hooks
  • Interesting smallish situational encounters fitting the theme/mood
  • Interesting smallish combat encounters

E.g. if during their investigation to fetch the magic mcguffin players want to go to the local pub for information, it helps if you have prepared a publician, the unsavory character they're going to interrogate, and whatever details are needed in your combat system to model a pub fight if one happens. Crucially, this preparation is usable no matter what plot-line brought them to that pub, what is the information they want, etc.

And the quantity of such resources makes a major difference between a 'railroad' campaign and a flexible one. If you have prepared a plot hook to interest them in the magic mcguffin, one location where they'll get directions to it and one thematic group of adversaries they'll need to fight to retrieve it, then the players must follow that track because you don't have any options. If you have two plot hooks leading to the magic mcguffin, one to save the princess, and one to kill the dragon; three different interesting situations/locations where they can get information leading to it, and combat stats for three different entities that can be used as adversaries (a band of orcs and an evil wizard and the dragon) then you have the ability to mix and match as needed to fit where the players are leading the campaign. Sure, they'll encounter just a fraction of what you prepared, depending on how their adventure goes - but the rest of the interesting material will be usable in some other session or game.


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