One of the pitfalls I discovered in my early days as a DM, was the tendency to “railroad” or lead my players on a track right into a storyline that I thought I needed them to follow. This, my beginner DM friends, is not a good thing. Players want to have free will. They do not want to feel their choices are either limited or of no consequence. Your job, then, is too provide them this free will, or at least the illusion of free will. It’s not that difficult to accomplish, and your players will appreciate it more. So let’s assume your players throw you for a loop in your campaign, and they take a path you hadn’t thought of…
Let’s assume your adventure called for the party finding a priest of Pelor who supposedly lives somewhere beyond the Howling Woods. They need his help because he holds a special Sunlight Ritual that a local farming community needs him to cast due to endless rain. Okay so you have your map planned out and you know that the priest resides in the Village of Eastwood, and you hope they stumble there eventually because it’s the largest village on your map. But your player’s decide to check out other spots on your map instead. They want to go to Evan’s Landing and then the Howling Woods. What to do? There are a few options.
Make things fit
This may be the simplest solution of them all, and the least obvious to the players. Whatever you had planned in Eastwood, adapt it to Evan’s Landing. The player’s wouldn’t really know the difference anyway. Unless you had a really good reason to keep your priest in the original location, this shouldn’t really be a problem. Your players have the illusion of free will, and your story can continue on its path.
Go with their flow
Okay, so the player’s have decided to go to Evan’s Landing but you really need Mr. Priest to live in Eastwood. No problem, let them go to Evan’s Landing. It turns out that a few farmers here have on rainy days, actually used the ritual from a priest in Eastwood. You can use the new location to your advantage. The farmer’s are willing to tell the party where this priest is, if they “help us out with something first…” The players will feel as if their free will contributed to their advancement in the storyline. As if they were supposed to go there and they figured it out.
Wing it
The player’s have decided that they are not only going to take their time in finding this priest, they want to explore a bit of the world you’ve laid out in front of them. “we go to the Howling Woods and look for evidence of werewolves. We’ll deal with the priest later.” What?! Your instinct will tell you that it’s easier to say “you find no evidence of werewolves” rather than letting them do what they want. This is wrong, wrong, wrong. In fact, this branching out can lead to greater plot hooks in the future that you may want to have in your back pocket. It may also lead your story back on track. Let’s assume the players investigate the werewolf activity. Maybe they can find a young werewolf with ties to Eastwood. He might be carrying a map of the village, or a note explaining his curse. “Help me, I’m Harlan from the Village of Eastwood, take my corpse to my mother and beg her to forgive me and my curse.” Use the party’s ideas and choices to open up story opportunities for your campaign.
Regroup your thoughts
Not everyone can be creative all the time. If your party really throws a curve ball your way, it’s always fair to tell them, “Guys, give me a few minutes to gather my thoughts.” Take a snack break and come up with something. Sometimes it’s a lot of pressure to sit there at the table with 6 sets of eyes staring at you while you think of something clever. Just be honest, they’ll understand. Bathroom break, phone break, or pizza breaks are good time for you to think without feeling the pressure.
Preparation is key
A good idea when dealing with these kinds of situations is to prepare and plan for them ahead of time. One way to do this is to have a flowchart or mindmap prepared, with the possible branches your players may take, and the options you’d have available to confront them. Flowcharts, as well as mindmaps can help you organize the many paths you can expect your players to take into a cohesive document for yourself.
A sample flowchart I found online... but you get the idea.
In closing, don’t allow your player’s actions to be game stoppers for you. They are entitled to, and should be able to make decisions. D&D isn’t a video game, and it certainly isn’t on a track. Let the player’s take off on their path, just be sure you are prepared to deal with it. Get ’em off your railroad!
www. Newbie DM .com 
Swordgleam
July 25, 2009
Those are all great ideas. I like to think that I make things fit, but I’m attached enough to my settings that I usually end up winging it instead. Which can sometimes be a problem if one area is stocked with higher level monsters – but hey, it brings the setting to life.
If you’re feeling stressed and tired, there’s one other option – come clean. Say, “Guys, I thought you were going to go to Eastwood, so that’s where all my stuff is. I’m not quite up to improvising today, so would you mind just going there?” Most groups will be understanding if you have to do this once and a while.
This tactic will even work for particularly exotic sidequests, one-shots or mini-campaigns. “Guys, I want to run a one-shot, but I don’t have time to account for your usual shenannigans. You’re all mercs who have freely agreed to find out what’s going on at Lonely Peak, and none of you want to kill each other. Got it?”
ElijahKaine
July 26, 2009
Newbie Dm,
Really good advice and something important I’ve noticed that DM’s tend to miss. Swordgleam’s advice is also great advice. I’ve had to come clean once and it went fine, they were understanding.
Geek Ken
July 30, 2009
I’d pipe up that being prepared helps tons. More importantly, being prepared for players to totally jump off the track. Having a few generic villain NPCs and a couple of lair/delve maps are great for when you have to improve a little.
And to slightly counter a point made by an earlier poster, sometimes it is okay to tell your players you are not quite prepared to jump off in a certain direction. But ask your players to giver you 30 minutes or so two whip something up. Usually you can have them take a little food break or break into a BS session while you get a few encounters together. Plus that extra time can allow you to move the players back on track after a short impromptu side-quest.
newbiedm
July 30, 2009
These are all great tips.
@geekken: that’s where the dungeon delve book comes in. remember, you can scale the encounters up or down about 5 levels, so in reality there are a countless number of delves there for all different levels.
Yach
April 7, 2010
That’s why I think the best way for a GM to go at it is with only the most basic preparation. You should have an idea of what might happen, but besides that, let the spontinaity grab you. Me and friends found hours and hours of fun doing the most random things. And the GM (usually me) had absolutely no idea where it was going to go at any time. I wrote a campaign for us to play through once; the whole twenty levels. I could have written it on a single sheet of paper though. Here’s what’s happened, here’s what’s about to happen. Here are some things that could happen in between. We got to about half of them, played it over two years. Tons of fun, and yeah, we got there. Just run it however would be funnest.
[Cue rant against 4e]
Anyways, yeah, a good GM can wing it, saying Yes, and then making it fit is one of the most useful skills ever.
[Cue rant on massive organized play]
I’m done, sorry, just felt like I needed to add my two silvers.