How to write your own adventure that doesn't suck?

By ddbrown30, in Game Masters

I've been GMing for many years, at this point, and I've yet to really create my own adventure. The one that was most "mine," was created by tearing apart the Tempest Feud module from D20 and replacing the story and a bunch of the connective tissue.

I'm currently trying to come up with something basic. My players are just about to finish the Dead in the Water adventure and I was thinking it would be interesting if they were then tasked with finding another source of droids. Now, let me be super clear , I'm not looking for suggestions on how to build that adventure. If you want to post some of that, that's fine, but please understand that this is not the point of the thread.

What I'm more interested in is how would you go about creating this as a fleshed out adventure? Something with multiple stages, interesting challenges and twists. Something that isn't just, "We found a place with droids. Go in there and get them." Or even if it was just that, how to do it so that the infiltration and extraction was interesting. Basically, how do you go from nothing to something entertaining?

Any links to articles would be hugely useful. Thanks.

To be honest, there's about as many answers to "how do you create a fleshed out adventure that doesn't suck?" as there are fish in the sea. Especially as different folks have different approaches.

Myself, I'm more of the "very basic outline, several sentences worth of summary for the basic plot, and improv the rest" school. Jay Little (creator of the system) uses even less, about maybe one side of a standard-size note card for his adventure planning. But a lot of that also revolves around knowing fairly specifically who the characters involved in the adventure are. I've been told I'm great at improv GM'ing, but I also know that if I get a bunch of random PCs whose abilities I have only the vaguest notion of, whatever adventure I'm running is going to fall flat and probably be a miserable experience for all involved.

The one suggestion that i can make is to tailor aspects of the adventure to include things that your players will want to engage in via their characters. Most published modules (especially those that don't include pre-gen characters) are written to be fairly generic in terms of how the PCs will interact with them. I've seen well-crafted professional adventures fall flat simply because there was no impetus beyond "well, this is the adventure I'm running tonight, take it or leave it" for the PCs to engage with that adventure, and I've seen and run ad-hoc off-the-cuff adventures that are fondly remembered because in various ways those adventures engaged the PCs and gave the players greater agency within the story.

As for the specifics, don't be afraid to pull from other media for ideas, especially action movies and in this specific case, heist movies (since odds are the PCs are going to have to steal the new droids). You've already got the hook, in that the Rebels need replacement droids, and the PCs are kind of to blame for bringing the droids from Dead in the Water onboard, making the whole mess kinda their fault. So being given a chance to get back into the Alliance brass' good graces by finding and acquiring new droids should be a pretty solid motivator, especially if you as the GM dangle a higher-than-typical Duty award to them.

If you're comfortable with a bit of winging things, don't be afraid to let your players provide you ideas on where to let the story go and what sort of encounters to include.

A couple of thoughts come to mind for me.

One is the guidelines that the RPGA gave to writers back in the day; they were, if I recall correctly, that every adventure should include a variety of encounters, such as a combat that could be avoided, a combat that couldn't be avoided, an obstacle that requires the use of skills, a role-playing situation, and others.

The other is advice from the old D6 2nd Edition rulebook, which is that you should think of some setpiece scenes, and then use them to build the scenario.

-Nate

Sounds like Donavan and I use similar methods or preparation. I like to do an outline that shows what the NPCs are doing and the general schedule of when they are doing it. I then adjust that schedule based on the PCs actions. If I have it scheduled to happen at X time but the PCs were side-tracked and took too long I then look at the event and decide if it would derail my story if it had already happened and the PCS are late.

His point about understanding the characters (IMO) is critical. You want to have points in the story where characters can shine. You don't have to plan events to rotate through characters like 1-2-3-4-reset, it can easily be 3-3-1-3-2-4 if you are on an adventure where one person has a bit more interested (or if obligation/duty was activated) but make sure you have something within the game for everyone.

The other piece of advice I would offer is think of cool "scenes" that you would like to see in a movie and plan an encounter around that. Most of the times, the players will deviate from your expected scene but will often make it much better. This is Star Wars so swinging over endless chasms, one man surprising and running off multiple stormtroopers, leaping out of a speeder to drop onto a passing one 100' below are all in the realm of possibilities. Give the players the chance to take those daring steps, even if they don't opt to take it.

I let my players know that I will always work to reward those type of heroics but Despairs do happen, it makes for an entertaining game.

As a GM who is still relatively new, I have gotten immense value out of Return of the Lazy Dungeon Master , a book by Sly Flourish. The advice there is wonderful for both constructing a usable adventure outline while allowing for plenty of room for improvisation. It's on Drivethru RPG or from the Sly Flourish site, and it's worth the purchase price.

I'm partial to the setup for the 5 Room Dungeon (note: need not be an actual dungeon, so named because fantasy games are popular).

  • Room One : Entrance And Guardian. The soft intro to the adventure. A short, usually physical, conflict to get the players interested in the adventure
  • Room Two : Puzzle Or Roleplaying Challenge. The cerebral conflict; it requires knowledge or social skills to complete
  • Room Three : Trick or Setback: the rising action. This builds tension and can even throw a wrench into the adventure. Either physical, mental or social conflict (usually choose what your players prefer)
  • Room Four : Climax, Big Battle or Conflict . Welcome to the "boss fight". It's the reason for the adventure, the "why are our PCs doing the thing? Again, could be a physical fight or a duel of wits, depending on the NPC and your players
  • Room Five —Reward, Revelation, Plot Twist. This is when your players "earn their reward". It could be treasure, it could be rescuing the price, etc. Heck, it usually entails sewing the seed for the next adventure

I've just started using it, so I don't have a lot of experience with it, but it's been working so far!

Just to reinforce what's been mentioned, knowing your NPCs, their motivations and schedule, is key.

For a small adventure with no outside repercussions it's simpler: the PCs get involved with an NPC because of something the NPC did; or the NPC reacts to the PCs intruding into their space. The starting point is easy to define and the resolution points can be clearer. With a campaign, sometimes I have NPCs "at work" in the background long before the PCs have even heard of them, though they might experience some side-effects.

Keep in mind you can define NPC pretty loosely. Mostly it's a sentient being or group, but sometimes it's the environment, or even something nebulous like a social movement. I mean, there's a whole series of movies based on people getting fed up with the Empire... :)

NPCs are far more important IMHO than set pieces. I just ran a murder mystery for friends while camping, and it was really fun how it evolved completely differently from when I ran it previously with my son. Timing of clues, whether or not there were shootouts, stakeouts, chases, the final showdown...all were different because of the way the NPC reacted to the PC's actions.

This is what I do to prepare unique adventures.

First there are two guiding principles that I abide by:

First; To quote Dwight D Eisenhower, "In preparing for battle I have always found that plans are useless, but planning is indispensable." The same principles work for RPG's.

Second: The essence of any art is making decisions.

With that in mind, I put together a document and outline specific details that might be relevant to the adventure. I write ideas out and that help me organize ideas. I detail NPC's as needed. This also forces me to research important elements to the game.

And then I prepare to improvise. In many respects, I'm ready to ignore half of the prepared information if necessary. I'll follow the adventure as the Players direct it and if I need to come up with something new on the fly, I can inject new stuff pretty easily.

For this campaign the format is pretty straight forward. I always start with a Mission Briefing (this works for an AoR campaign but not so much for EotE), then I put together Mission Details. Items that are based on the briefing and elements that should come up during role playing. I have (of late) added a section for NPC OpFor statistics 'in case' combat breaks out. (I didn't prepare combat stats for the following mission as the PC's were supposed to run through this adventure sans combat. An oversight that I quickly remedied as needed . . .)

The following is the Campaign Notes that I prepared for my first session. While it seems like a lot of data there is quite a dearth of data and I still had to make up a LOT on the fly. This document will also NOT let you know what actually happened in session.

But this is what I do and it seems to work for me. The following document was last modified on 1-09-2018 and the players are currently on Mission 022 -- "Unwilling Greeting."

Mission 001 – Graceful Battery

DC01

Mission Briefing to the PC's

PC's are introduced to Nath Searrail (Bothan [m]) operative who is visiting. (Nath arrived in his U-Wing Chjovek 027 ).

Nath has received a dispatch from an agent and recruiter on Sullust named Wonn Kongurss (Unk Gender by Nath). Wonn is reporting that there are four recruits in a safe house, ready for pick up.

The two have never met and besides the dead drop, Nath's only way to contact Wonn directly is Dr Dalent Yiggath who works at Medical Department D-19 in the city of Keloresh (a main commercial star port).

DC01's mission is to make contact with Wonn, and extract the four recruits. Next, Transport the recruits to the Deveronian Promise (N16) at an barely charted M9VI (Code named 'Excitement 37') between Kira & Pax (Same sector N16) in 7 – 10 days. If they miss the 10 day window, they will be considered overdue and the Deveronian Promise will depart.

Base Travel Time between Defiant Core on Innton(M18) and Sullust(M17) is 12 hours.

Base Travel Time between Sullust(M17) & the Rendezvous coordinates (N16) is 29 hours.

After meeting up with the Deveronian Promise , return to Defiant Core.

Mission Info:

Source is Nath Searrail (Bothan (m) operative). Nath has a dead drop with Wonn Kongurss and the two have never actually met. Wonn is operating out of the commercial port city of Keloresh.

Nath picked up the report that Wonn has four recruits who are requesting extraction and integration to the rebellion.

The only known contact for Wonn Kongurss is a Dr Dalent Yiggath who works at Medical Department D-19 in the city of Keloresh (a main commercial star port).

Travel Distance: Sullust (M17) is one sector away from Innton (M18) and both are on the Rimma trade route. Base travel time is 12 hours one way.

Wonn Kongurss (female Sullustian) is an established rebel agent/recruiter and she has found four Sullustian recruits who want to join the rebellion. Wonn is an ambulance medic and her “emergency contact” is Dr Dalent Yiggath who works at Medical Department D-19. (Yiggath is a friend but he doesn't know anything about Wonn's rebellious activities. He may turn the group into the Empire).

:: Puln Urias – Older and wealthy. He has a two tons of gold that he wants to donate to the Rebellion. Smuggling the gold is going to be tricky, especially since his cousin Uidu Jocb has stolen half of it. Puln doesn't dare inform the authorities because Uidu will out him as a rebel. Puln does know that Uidu is meeting with a commodities broker in two days who will be converting the gold to Imperial credits . . . (I need a layout for Uidu's palatial estates & security arrangements).
:: Hild Schest – He's a fair pilot and eager to learn and eager to be useful. Outgoing and a bit reckless.
:: Takk Urba – Takk is a politician and fancies himself an orator. However he is staid and uninspiring.
:: Hagg Bdemb – Hagg is quiet and unassuming. He doesn't think he has much to offer but has two ranks in shooting (Light & Heavy YYG).

Cpt Collan Chawill is a Human male, ISB counter intelligence agent. He is nosy and suspicious by nature and makes it his business to keep tabs on all non-Sullustian's who visit the world, especially if they start interacting with the locals. He has several Human & Sullustian agents who quietly report to him, but traffic in Sullust is overwhelming his limited resources.

Uidu Jocb is the larcenous cousin of Puln Urias. He is making arrangements to sell his cousins 100 count 20 lbs ingots of gold to the Empire for the awesome deal of $ 15,000,000 credits. He is waiting for an Imperial Broker named Dr Geeus Venken (who will be arriving shortly from Corscant) to arrive and certify and authenticate the gold for the Empire.

Tellia Ventriss is employed by Uidu's household as a facilitator and liason for Uidu's non Sullustian business deals. She will be coordinating with the PC's and 'claims' to be quite familiar with Dr GeeusVenken. Once she can approach the PC's quietly, she'll offer to disclose to the PC's the location of the half of the gold that Uidu is storing (at his home) in exchange for two of the ingots.

Dr Geeus Venken is a human chemist who has been asked by Cpt Collan Chawill to certify the ingots of gold as real. He is enroute from Corscucant and will be arriving in 36 hours (from current timeline).

Also Ji Kez needs some parts and supplies for the aging Z-95's. Could the group see if they could pick some up? He knows a guy Zic Keescirss , who works in SoroSuub's shops as a technician. Zic does a lot of on the spot repairs and has a reliable network of suppliers. Ji provides a residential address for Zic to the PC's. Itheme is Zic's wife & they have a daughter named 'Hulde' (who is going to find Choten intriguing).

Plot Points:

Seiss Kegnur (Sullustian Male) is the on duty customs inspector who meets up with the crew when they land and does his meet and greet. He'll collect $100 CR per dium for berthing fees or offer $500 per week. Seiss points the PC's toward consumables vendors, & as far as declarations and manifest checks, he points out that his Imperial minder has wandered off and he's willing to skip the whole process for just $50 <wink nudge>. If the PC's pay the bribe, Seiss will point them toward Jiss Rujand.

Sleepy Nudge.

Vectress. This is the Offworlder entertainment establishment where Jiss was arrested.

Red Herring:

A Sullustian Female: (Jiss Rujand) alone and eagerly, is accosting foreign merchants trying to get information or a ride so that she can join the Rebellion. She is approaching likely people at the Gooden Yish Cantina which caters to off world ship crew. She is arrested at the Cantina, as the PC's enter the cantina. Collan Chawill is on site & in uniform for this arrest as he's been following Jiss for about a week. Jiss was arrested by 20 Stormtroopers as the PC's arrived.

Gee Joolonn is a window washer who will approach the PC's (Nix) when they return to the ship. She'll point out that the ship looks like it hasn't been cleaned and offer to wash the windows plus detox the surface to protect the ship from the effects of Sullust's corrosive atmosphere. Her price is $ 25, but she can be negotiated down by a knowledgeable technician. (Sullust's atmosphere isn't that caustic). Gee also knows that Seiss tends to hang out at the Blizz Took; It's a “Shroom pit” but still cleaner than most and caters to locals (since some of their fare will kill offworlders, whereas it's Sullustian clientele are just 'buzzed').

Extraction Plan:

The PC's are expected to report to the Deveronian Promise (N16) at an barely charted M9VI between Kira & Pax (Same sector N16) in 7 – 10 days. If they miss the 10 day window, they will be considered overdue and the Deveronian Promise will depart.

Base Travel Time between Sullust(M17) & the Rendezvous coordinates (N16) is 29 Hours.

To follow up on my previous suggestion, the Lazy Dungeon Master series of steps are as follows:

1. Review the Characters: This means revisiting your PCs and their motivations. This allows you to stick things in there that will play on their backstories, motivations, and needs.

2. Create a Strong Start: This is your opening scene, which you set up the problem to be solved. This scene will lead to all other potential scenes in the adventure. Better to make it engaging and exciting than dull and ho-hum.

3. Outline Potential Scenes: Optional step. Nothing too definitive. Just ideas for possible scenes at this point based on the problem you set up in step 2.

4. Define Secrets and Clues: This involves figuring out the situation the PCs are going to uncover through their actions. This means the secret schemes of the Hutt crime lord, the true killer of the body they found, the Emperor's plan to kill all Squib Jedi, or whatever. It can also mean actual clues, but it doesn't have to, as Sly Flourish advocate for "floating clues" that can be inserted in various locations depending on what the PCs do.

5. Develop Fantastic Locations: For Star Wars, this might be read as "interesting locations." Basically jot down some interesting and memorable details about likely places the PCs will go. Maybe find a map online. Figure out who might be there and when. But keep it fairly basic.

6. Outline Important NPCs: Who are the PCs potential allies and adversaries? What are their motivations? What are they going to be up to while the PCs are out adventuring? Also involves creating a capsule personality; the author advocates associating a popular fictional character with each important NPC to give you roleplaying ideas.

7. Choose Relevant Monsters: For Star Wars, think adversaries. This is about having stats handy for your session. Compile likely Minions, Rivals, and Nemeses (including those from Step 6) in preparation for play.

8. Select Magic Item Rewards: Just ignore the "magic items" part for other RPGs. What do the PCs get if they succeed in the mission? What happens if they lose?

Edited by SavageBob

I'm pretty sure there's guidance on how to cater for each career in the career splat.. Maybe I imagined it or dreamt it...... you could start there.

Edited by ExpandingUniverse
7 minutes ago, ExpandingUniverse said:

I'm pretty sure there's guidance on how to cater for each career in the career splat.. Maybe I imagined it or dreamt it...... you could start there.

You didn't imagine it. But that same advice can be a bit much if a GM is trying to cram it all into a single adventure, and some of those chapters lean a bit into the stereotypes of what a career should be in the view of how the designers described the career in the line's respective corebook.

You dont come up with a adventure, you make a hook, plan some loose plotpoints, get some NPCs will certain motivations and let the players write it themselves. One of my all time best sessions was when my group decided to raid a arms factory for some weapons for their allies, I had very loose ideas and just rolled with the punches. Some hilarity and genius roleplaying happened.

25 minutes ago, Donovan Morningfire said:

You didn't imagine it. But that same advice can be a bit much if a GM is trying to cram it all into a single adventure, and some of those chapters lean a bit into the stereotypes of what a career should be in the view of how the designers described the career in the line's respective corebook.

I was thinking of considering this for Obligation.. mindmap or bullet point an idea or two for each career and put them all in a separate file (that's my OCD right there) with any related minions or creatures, bounties, items, historical sites.. and here I was trying to not over-prep *facepalm*

Over (many...too many) years and systems, I've learned that less can be more.

When I first GMed waaaaaay back in high school for our DC Heroes RPG campaign, I definitely overprepared. I would literally write everything out using the same format as the system's published adventures. I was nuts.

As I moved on to other systems, notably the WEG Star Wars system, I'd still do a lot of prep, but not as rigid.

With this system, I've reached a great comfort level with just noting story beats that I want to hit and prepping NPCs that they're likely to encounter, but whenever possible, those elements are flexible in terms of location. Then, I just roll with what my players throw my way. I've had encounters that I expected to be combat encounters turn into purely social encounters...or get bypassed altogether because of the decisions they made. And if I really, really liked the idea of that encounter, I can just set it aside and reskin it for a later date.

As a side note, while designed for Genesys, GM Hooly's Episode Beat Chart could be useful to you, as well.

I aim for an overtly character-driven story, which becomes easier as the game progresses. It takes time for players to develop their personas and become truly engaged with the story.

In session zero of my current F&D game, which takes place on a single world, in a mining boomtown, we discussed and developed a number of NPCs to represent the various factions of our setting. I requested their characters had well-developed back stories (for me to draw themes and hooks from), as well as a lie-the-character-believes (to facilitate character arcs). I also started them on 3 parallel journeys, not as a party.

I started the campaign by intentionally driving the characters to the point of exhaustion (sessions 1-7 were a single, extremely eventful day). By the end, they were overwhelmed and in desperate need of a break. Adversity reveals character, so by pushing the characters to the brink, the players have gained additional insight into who they've created.

Session 8 was completely unscripted. I already knew what the NPCs were doing and/or pursuing, so I didn't need new material. The characters drove everything, continued to reveal new aspects of themselves, and forged bonds to each other without any manipulation or GM fiat.

Session 9 will mark the 25th hour of game play and the end of Act 2 of the first "movie". Revelations are coming and they will have to make some hard choices on what comes next.

Why, there's a book about that: How To Write Adventure Modules That Don't Suck

However, many people have said there isn't a "right" way, you really have to find what works for you and your players. If it's not fun for you to prep, then it's not right. So grab the reigns of the things that excite you and it will come through in your adventures. I guess this is sorta meta advice but it applies regardless of how you approach it.

Lots of good advice all around. (Kudos to you other awesome GM's as I heartily endorse and study your Gamer Fu).

I'm taking a break from working on "Mission 022 - Unwilling Greeting" which is turning into a PC driven mission . . . however, I'm naming this chapter "Many Bothans Died" and the players already understand what this mission is for. Yes, they've become the witting pawns in the hunt for the location of the new Death Star! (Totally no spoilers here).

As I do, I realize that I'm setting up a travel log journey from darkness. :blink: But on the plus side, I've already done one of these with the players and it turned out pretty well.

So for starters here's the mission parameter. (There's not going to be a "Mission Briefing" because the PC's supervisors don't know what the PC's are doing . . .)! :o

Josus' [One of the PC's] Bothan sponsor has discovered that the Empire has hired a Given research team to create and transport super frame girders for a massive spherical structure . . . Rumors have it that they're building 'something' at one of the lagrange points in Yag'Dhul's orbital plane. DC-01 is asked to secure a shipment to Yag'Dhul and deliver the goods so that they can investigate this building project.

Next, knowing (kinda) what the 'end' is, I've put together a partial travel Itinerary for their new beloved C-ROC the Lucinda . While the players don't necessarily know where this intel lead will take them, I as the GM have decided that this is where the path of breadcrumbs will lead them.

Lucinda Travel Itinerary: (Note that they have a Class 2 Hyperdrive installed and travel times are for that speed).

Depart Bothawui (R14) and Arrive Nexus Ortai (Q14) :: Travel Time 1.5 days (36 hrs).

[Time on station]=

Depart Nexus Ortai (Q14) and Arrive Iseno (N13) :: Travel Time 8 days (192 hrs).

[Time on station]=

{Razza will arrive on Iseno 10 days (240 hrs) after departing from Bothawui}.

Depart Iseno (N13) and Arrive Wroona (L15) :: 6 days (144 hrs).

Depart Wroona (L15) and Arrive Yag'Dhul (L14) :: ~0.5 days (10 hrs).

Depart Yag'Dhul (L14) and Arrive Vandelhelm (M15) :: 2 days (48 hrs).

Depart Vandelhelm (M15 and Arrive Nkllon (Secret Ort Cloud Manufacturing) (L16) :: 2.2 days (53 hrs).

The Razza rendezvous is bolded for a reason. THE PLAYERS SPLIT THE GROUP! (Those . . . PLAYERS)! . . . fine. I'm going to take away their other ship. ;) There's a 12 hour gap between those two ships for the rendezvous so time on station for the Lucinda is something that I'll need to track. The more time that the crew of the Razza spends on Iseno before the Lucinda arrives, the more time the Sabacc shark can get into trouble. :lol:

But I digress. I don't actually know what the PC's are going to do and how long their misadventures will take. I do however know that the Razza will arrive at Iseno in 10 days. (It's manned by NPC's so . . . not that big of a deal really <_< ).

The next step in my preparations is to figure out details about those destinations that are relevant to the campaign. I'm checking Wookieepedia to see what information is there and I'm going to be making up a ton of information to fill in the gaps.

One of the tools that I use is a file that I call "Slugs & Thugs." It's literally a list of locations and the people associated with those locations, listed alphabetically by location. (My Slugs & Thugs for my Star Wars RPG is currently 21 pages long and it will be growing rapidly as this mission gets put together).

But to my benefit, one of the systems that is on the itinerary is Wroona (L15) and that's a location that I've used previously and the players will be returning to work with Rebel assets that they've worked with in the past. I'll be able to do some call backs and reuse material from earlier on.

This itinerary also lets me know in what order to do my prep work. I'm currently focusing on the details for Nexus Ortai (Q14) and will work on Iseno (N13) next. However . . . based on what the players do, they may deviate from my itinerary as they come across new information and if they figure out what the clues that I've been dropping mean. :ph34r:

I generally use the three beat screen writer's method.

Introduction-Complication-Resolution.

You can add beats (usually two more) by adding complications, rising tensions, surmountable failures, or a social interludes (if appropriate).

Once I have that very basic outline in place I decide on a short list of key NPCs.

I then jot down 2-5 bullet notes akin to FATE aspects for each beat and each key NPC.

If I have a cool idea for a big set piece I make a few notes for that, too.

From there, I shamelessly wing it.

I started doing this after an abortive attempt at running FATE. It was too amorphous to be playable (for me.)

Aspects are , however, a brilliant way of distilling character concepts and ideas.

Just to add my 2 credits to the already excellent advice.

I plan per session, instead of writing out an entire adventure. Especially for a sandbox-type game. Now your major villains plans and motives. Get that super detailed. Then decide how the villain will react when the PCs inevitably intervene.

Example, (I've been DMing D&D lately, sorry for the off-genre example) Knowing your villain : the BBEG is the cousin of one of the PCs, she is trying to become a lich, she has made a deal with a dead god: thousands of souls for sacrifice in exchange for lichdom. But she doesn't like that she'll be beholden to this deity. So she found a way to get her lichdom but then free herself from the god's control. She has a talisman of the god and a relic that allows her to convert an entire city of people to her will. She'll capture all of the towns and cities in an area. But she needs a different relic to for her freedom from the god, this relic is under the city the PCs have used as a base of operations for the entire campaign. She'll use her army of thralls to capture the city and steal the relic in the crypt beneath it. She uses her own cultists and has made alliances with a demon and a beholder to supply troops. She will win if the PCs do not intervene.

Then you plan per session based on what the PCs did last session. Example: last session the PCs witnessed first hand the BBEG capture one of the cities using the talisman and relics power. For this session, they should now have to escape the now corrupted city and warn their home city of the threat. But they could do other things. But they are dealing with a city that has literally turned evil and an evil army just outside the city. So they'll need to be stealthy most likely.

Then just improvise if they do anything else other than the above. You know how the bad guys will react: kill/capture them, and you have a pretty good idea how the PCs will proceed, so you just have to wing the unplanned stuff.

I once had to improv the PCs talking to an ancient red dragon that I absolutely did not intend to happen! But thats the way it goes sometimes!