Map, Monster, Chest: The Golden Trio of Adventure Design

The Golden Trio of Adventure Design

RPT GM Benjamin asks:

For an anxious and inspiring GM that tried to learn way too much for what is actually needed, how do you just sit down and say, “I’m doing this random plot, with random PCs, and keep everything afloat and fun?”

My brother can improvise anything and I’m literally the opposite. Most likely it’s simply a lack of improv skill (or the lack of confidence).

Even with all the resources, why am I unable to write and run a game? It’s not a movie with a script. It’s not a video game because the roleplaying points are the “movie” scenes and it’s impossible to have prep information flow like a book.

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Hi Benjamin.

Thank you for the great question. Improvisation is indeed a skill that you can master! How do you start with nothing and improvise an entire adventure that’s creative, runs smoothly, and can be prepped in an hour? This problem is dealt with head-on in my Master of the 5 Room Dungeon workshop, and I’ll share a key tip from it with you today.

I use the 5 Room Dungeon framework because it has mythic story structure baked in, based on Joseph Campbell’s Monomyth model. If you follow the 5 Room Dungeon formula, you are guaranteed to create or improvise a good story.

In addition, a core technique I teach in the workshop is called Map, Monster, Chest:

  • Map: Location.
  • Monster: Foe, monster, obstacle, or conflict.
  • Chest: Party goals, treasure, reward, and adventure progression.

I initially encountered this framework in one of Aron Christensen’s books (affiliate link). He calls it Map, Monster, Treasure. I added a bit more juice to the treasure component, and call it Map, Monster, Chest.


When coming up with encounter ideas for your adventures, start with Map, Monster, Chest. I usually go with adventure conflict (Monster) first.

What foe is here?

For example, open your monster book to a random page and point. That’s your Monster.


Let’s say you opened your critters guide and pointed at a gorgon. I then ask, What location (Map) would make sense for that foe or conflict?

What would be a cool lair for my monster?

For a gorgon that has petrification breath, I might have a lair that has a hall filled with lifelike stone statues, for example.


Finally, what’s the reward (Chest) available in the location?

Perhaps there’s a way to use the gorgon’s body parts to restore petrified victims to life, and those rescued will offer some of their possessions to the party in gratitude.

Harvest Ideas

It’s hard at first because you might not have a lot of experience nor an internal “library” of ideas to work from. Grab ideas from books, movies, AI, and other RPGs. Copying ideas and turning them into adventure material will help you remember them in the future for faster ideation.

Prepare to Improvise

Searching online for random tables and generators, or buying books with such, offers another huge well of ideas for your improv. Curate tables ahead of time so you can roll or pick during sessions when needed.

A Good Approach

To avoid railroading, another tip from the workshop: you deliver the What and let players figure out the How. All you need to do is set up encounters. It’s the players’ job to figure out how they will tackle them.

Also try to avoid predicting what players will do and directing such character actions. This leads to a lot of GM stress. “The characters will discover the secret door, find the magical gem, then go to the throne room and place the gem in the top slot. They’ll then summon the villain who will escape but not before cursing the party.” That’s a recipe for disaster as you won’t know what choices players will make or how the dice will roll.

Instead, create locations (Map) filled with encounters and run the locations like a strategy game. For example, a nanobot factory will have several expected locations for supplies, waste, and building bots. Several locations will have foes, obstacles, and conflicts (Monster). And in those locations or nearby are things and information the party would find valuable (Chest).

Map out your nanobot factory, stock it with these things, and then set players upon it. What they do is up to them – you need only referee outcomes. You might also give thought to how certain features of the nanobot factory would respond to a party intrusion, so you have those ideas ready.

This approach is much less stressful than trying to foretell a narrative, and it gives players more freedom to make their own lives more complicated. 🙂

Improv With Map, Monster, Chest

Try this approach to sketch out a few adventures or 5 Room Dungeons. Get a bit of practice with it, because this makes a wonderful improvisation framework. Next time you need to create an adventure on-the-fly, just ask yourself:

  • Map: Where does the adventure take place?
  • Monster: What is the major monster or conflict?
  • Chest: What reward would draw the party into your adventure?

From those three facts, you have a solid framework to hang the rest of an improvised adventure from. And if you employ the 5 Room Dungeon method, then you get guided improvisation for at least five encounters that will deliver a complete story.

I invite you to carry on this conversation at my Roleplaying Tips Discord. You’ll get great tips from GMs there to help you on your quest to prepare and improvise great adventures.

I hope this helps, Benjamin!