Preparing a Classic D&D Module for OSE

Running D&D module B4 The Lost City in Old School Essentials was a success. Our group enjoyed a slightly revamped version of a classic adventure. And only a couple of player characters died! I can't say that Zargon and his cult were happy with the outcome, but they got what was coming to them. I credit the experience to a good group, my ability to improvise whenever players do the unexpected (which is all the time), and the efforts I made beforehand.

A gamemaster's homework is never done.

Step 1: Read the Darn Thing

It doesn't matter if it's the first time or the hundredth time. No notes. No highlighting. Just go through the whole thing and get familiar with the contents. What are all the pieces and how do they fit together? What stands out? What works and what won't land with this particular group of players? What doesn't fit with how I like to run things at our table? What is so iconic that any alterations would only lead to bitterness and despair? None of these questions can be answered without knowing what's in the adventure.


Step 2: What Changes?

Outside of the occasional one shot, adventure modules aren't played in isolation. They have to fit into existing campaigns. In this case, the Nostalgia Tour concept. The Lost City couldn't overstay its welcome or it would push out another classic module. I needed to wrap it up by the time the player characters reached third level and were ready for the next module.

I originally wrote a bunch of details on the changes I made, but that turned into a whole thing. The changes and the thinking behind them will be presented in that mythical time we call later.

(EDIT: Later turned out to be a week and half down the road. Here's a post about all the changes I made: Remodeling B4 The Lost City.)


Step 3: Attack the Module with a Highlighter

Classic adventure modules weren't exactly masterworks of organization. The need to present information to the GM by embracing the tools to technical writing - bolded text, bullet points, and otherwise separating out critical statements from a body of text - wasn't fully identified until more recently. Since there's no way to add these features to an existing module with rewriting it, I used a highlighter to make key information stand out.

I'd be squeamish about marking up a vintage module this way. Even a damaged copy is still a decades old document at this point. Fortunately, I was able to avoid the issue with a print on demand copy from DTRPG.

Here are examples of the kind of information I highlighted:

• How the traps are supposed to work. What does a player character do to trigger the trap? What happens when the trap is triggered?
• Reactions for monster encounters. What do they do when they encounter the party? Otherwise, I rolled on the reaction table.
• Motivations for NPC encounters. What does this NPC want from the party? How do they respond based on the reaction roll?
• Treasures and other loot. This information was sometimes buried in the room descriptions.
• Key historical facts. The Lost City has a backstory relevant to the adventure. I wanted to keep the critical details handy.

Step 4: List Making

Although a highlighter makes critical information easier to find, I wanted to have some things at my fingertips. Lists make it possible to reference certain things without having to flip back and forth through the module.

Examples of my lists:

• Static monster encounters. The rooms and the bags of XP dwelling within them organized by room number. It worked as a checklist of what the party ran into as they moved through the dungeon. I included each monster's page number in the OSE Referee's Tome for easy reference. This made it handy during combat and for calculating XP in between sessions. Easily the list I used the most.
• Wandering monster encounters. Includes the page numbers of each wandering monster table from the module. As with the static monster encounter list, I also included each monster's page number in the OSE Referee's Tome. Not as useful as I expected. The dice were not cooperating and I didn't roll as many wandering monsters as I expected.
• Trap encounters. Room numbers and a description of the traps within them. Having the information in one place wasn't as useful as I expected. The work I put in with the highlighter was enough for me to find the information when I needed it.
• NPC encounters. Statistics, descriptions, significant items, and spell lists for encounters that might result in talking, fighting, or some combination of both. The descriptions of some groups are spread throughout the module. Compiling them in one place saved some time during play. It also helped me keep the names straight.
• Cynidicean encounters. The inhabitants of the titular lost city have their own sub-table in this module's wandering monster tables. Since I needed to convert them to OSE anyway, I retyped the (converted) statistics and descriptions on a handy reference document.

Step 5: Old School Essentials Conversion

Although OSE is based on Basic D&D, certain things required adaptation. Most of the monsters have statistics in OSE, but the ones unique to B4 The Lost City needed work. The biggest issue involved our group's decision to go with ascending armor class as an option. All things considered, the conversion process was easy. Converting an AD&D module to OSE might involve more time and effort. I'll be burning that bridge later in the Nostalgia Tour campaign.