How to be sure that an adventure is short enough to end in one session?

Question

Recently I am in the situation where I have to start mastering some adventures to people I don't know. They can have some experience or not at all.

It's needed to end in just one session, because it's inside an event and can't be continued another day.

I didn't decided the system, but I'm trying to find one who can be explained in less than 20 minutes. Probably a simple trad game, WoD or a percentile system like CoC.

I am going to use pregenerated characters and the story will involve a little investigation and one or two combats that can optionally be solved diplomatically.

The problem is that I don't know how to calculate the time of the adventure, I see too many variables here.

Do you have any trick or system to know if an adventure is short enough to be played in just one session? (Probably like 3-4 hours)

Answer 1

It's never foolproof, but there are strategies that will help:

• Keep the goal straightforward and compelling. This minimizes the possibility that they'll start wandering around and get off on tangents. You don't want to 'railroad' by forcing it, so aim for something that they won't want to deviate from. Ambushes, 'fetch quests', rescues, escort missions, stuff like that are all good. If they're strong role players, then aiming for their character motivation is even better.
• Minimize detective work. Once you get them in the mode of investigating, it's hard to stop - and it feels strange when the DM interrupts it to get things moving again by having the information drop in suddenly.
• Actively control pacing. Some players obsessively get into time-consuming activities - like, searching for secret doors - and you will have to be good about figuring out why they're doing it, and helping them move on without it becoming a time sink. There are a few ways to do this, from pressure (your character knows that a patrol will be here in a few minutes, what do you do?), hand-waving (ok, you spend 30 minutes to ransack the room and find nothing), and as a last resort, 'character knowledge' (your character doesn't see any of the tell-tale signs of hidden compartments or secret doors that they're trained to look for - like marks in the floor, or lots of visible seams in the walls - so it's safe to move on).
• Make it modular #1. Figure out the simplest possible path the characters can take, design for that, then figure out some interesting 'complications' you can add in if they sail through things too quickly. That way, you are ready if they are exceedingly lucky or clever.
• Make it modular #2. On the flip side, if your original design has four 'steps' and they take far too long on one of them, figure out how to skip one of the middle steps ahead of time. They'll never notice.
• Start with party unity. If this is a new party, make the characters have a strong bond that defaults to strong teamwork and coordination. They work for the same organization, or have known each other since childhood, have similar (and good) alignments, stuff like that. If it's an existing party, see if they're open to introducing a narrative element like that. I've found that asking them to figure it out for themselves and give you the basic idea to work with will get them really engaged.

Hope this helps!

Answer 2

Here are some things that have worked for me:

1. Create a timeline for when certain things need to happen in order to meet your time goal.
2. If the group is willing, mention the time goals to the players. Some are competitive enough to try to meet those time goals.
3. Develop shortcut clues for them to find that lets them bypass some encounters or go straight to the conclusion. Use these if you fall behind your times. Having the clues created ahead of time will make it seem more like the players are on the adventure that you planned.
4. Another option is to drop some encounters completely. If there are three rooms the players need to get through and the players don't know that there are suppose to be three rooms, removing one (or two) will have no effect on their enjoyment.