How to Prep a D&D Session in 30 Minutes

This is a complete prep for session nine of a running campaign. It took thirty minutes, it fits on one card, and it was enough for a full evening of play:

Last session, the party escorted a salt caravan, discovered that the caravan master was smuggling stolen relics, and let him go in exchange for a map. Every line on the card comes from that. There’s no plot, no ending, no “and then.” Just a world reacting to what the players did, and three places where that reaction will hit them. The rest of this article is how you get from last session’s notes to a card like this before the first player logs on.

Why Prepping From Scratch Takes So Long

When prep feels slow, it’s usually because you’re inventing too much, not writing too much. A blank page asks you to come up with the whole session on your own: the plot, the villains, the twists, the reason the party should care.

In a running campaign, you’re never really starting from zero. Last session the players killed someone, insulted someone, took something, or promised something. Every one of those choices pushes on the world, and the world pushes back. That push-back is your next session. Asking “what happens because of what they did?” is much faster than asking “what should happen next?”

The Ripple Method: Six Steps in 30 Minutes

Think of last session as a stone thrown into water. You’re prepping the ripples it left, and each step below either finds them or turns them into something you can run.

1. Look Back

Start with whatever record you have: your notes, a player’s recap in Discord, a recording. Don’t try to remember the whole session. Look for the last scene, the decisions, and any new names.

If you don’t have a record, that’s the first thing to fix, because this step is the one the whole method rests on and the one most DMs skip (nobody wants to write a recap at midnight after four hours behind the screen). Our session recap template takes about ten minutes, and there are other ways to remember what happened last session if writing isn’t your thing. If your group plays on Discord, Kazkar can record the session and write the chronicle for you, so on prep night you open last session’s recap instead of a blank page.

2. Find the Ripples

Ask three questions about last session and write one line for each answer:

Three to five ripples is plenty. You don’t need to use all of them. The point is to have more than one option, so whatever the party does, something is already in motion. If your campaign has a lot of names, a simple list of NPCs and places helps here. We covered that in how to track NPCs, locations, and lore.

3. Pick the Opening

The first five minutes set the energy for the whole night. Skip “you wake up at the inn” and open with a ripple arriving at the party’s door:

• The merchant they robbed sends a messenger.
• The cultist who escaped has left a sign on their door.
• The town they saved throws them a feast, and someone at the feast doesn’t belong.

One or two sentences is enough. This is your guaranteed scene: whatever happens later, you know how the session starts.

4. Sketch Three Scenes

This is where most of your time goes. Write three situations the party could walk into: three separate places or encounters, each with a few lines, with no fixed order between them. For each scene, answer just three things:

• Where is it, in one sensory detail? (“A mill that smells of wet flour and smoke.”)
• Who is there, and what do they want?
• What’s the problem or choice the party faces?

Players won’t follow a script, so don’t write one. Three loose scenes give you something to grab no matter which way they turn.

5. Names and Numbers

Two things kill the flow at the table: making up a name on the spot, and flipping through the Monster Manual mid-fight. Fix both in five minutes:

• Five spare names, ready for any NPC the players decide to talk to.
• One encounter: the monsters and their page numbers, or a link to the stat block.
• One reward: an item, a clue, or a favor the party can earn.

You don’t need maps for every room or stats for every guard.

6. Put It on One Card

Everything above should fit on one page. If it doesn’t fit, it’s too much for one session. Here’s the blank version of the card at the top of this article:

SESSION [number] · PREP CARD

LAST TIME   [where we stopped]
RIPPLES     [who reacts] · [what's unfinished] · [where they want to go]
OPENING     [first scene, starting with action]
SCENES      1. [where] · [who wants what] · [problem]
            2. ...
            3. ...
NAMES       [5 spare names]
ENCOUNTER   [monsters + where the stats are]
REWARD      [item / clue / favor]

What to Skip

Fast prep is mostly about knowing what not to do. If you’re short on time, drop these first:

If this approach sounds familiar, it’s close in spirit to Mike Shea’s Return of the Lazy Dungeon Master. His checklist is a great next step, and we wrote about it in lazy DM campaign documentation. The version here is for nights when you have even less time: start from last session and let it do half the work.

Make Next Week’s Prep Shorter

The cheapest prep happens at the end of the session you just ran. Stop on a decision or a cliffhanger, then ask the players “What are you planning to do next?” Their answer is Step 2, already written, and a quick recap that night covers Step 1. If it’s been weeks or months since the last game, start with our guide to restarting a campaign after a break before you prep.

Do that, and next prep night starts with a card that’s half full. Your players already wrote that half. You just have to read it.

Frequently Asked Questions