Ah, you know the feeling well don't you? Your game has been going at a good pace, plot elements are falling into position, and the team is really gelling and moving forward. You're all set for the next session, where you will reveal that the villain is actually one of the PC's father/mother/friend/dog's therapist, and all the drama that goes with it. This development is also central to the short term needs of the plot, and really you've got it all set to go. There is only one problem, that player won't be able to make the next session. So, what do you do?
Well, first of all, hopefully the game isn't already mid scene where you called the end of last session. This happening a lone is why I don't like to end sessions in the middle of anything important or dramatic. People's schedules are wonky, and I'd rather not have to cancel a game because 1 of 6 players can't make it, and their character is important to go on. For now, we're just going to assume that the players are starting from some neutral point, with nothing super pressing coming down on them. The plot elements are ready to go, yes, but they're not firing on all cylinders yet.
Now, if that is the case - and believe me, with some pacing and time control in your sessions you can make this the case more often than not - then we get to take a big hint from our old buddy the television series. What is that, you don't watch TV? Alright, well I'll explain it to you. In a lot of American prime time shows, there is a meta plot that is running over the course of the season. Only, every episode doesn't actually work towards that goal directly. Out of a 22 episode season, maybe 6-10 of them are directly and primarily focused on the main plot. The other 12-16 episodes? Filler. Important filler, but filler none the less. They give the audience time to digest the plot developments that just happened, and for the audience to see how the characters are reacting to the changes that just happened.
Comic books do something like this two, only there it really is just filler. A side story that is ready to be printed to fill in the gap, should something happen to slow down production of the next chapter in an ongoing story. Manga, for the Japanese equivalent, will sometimes have filler arcs, and the anime series that are based off manga are sometimes notorious for the length of filler arcs they can have.
The point? Try to have a side story or two ready to go just in case. It doesn't have to be huge, but something amusing that will occupy the player's time, can be finished in one night, and will more or less leave the world back the way it was when it was done. A zombie invasion is bad for this. A bank robbery is good. See the difference? Zombies rise up, and odds are you have hundreds dead, and the lingering fear they'll be back soon. Bank robbery, well, you stop that and you get in the news, but life returns to normal for everyone else really quickly.
With this side story in hand, you don't have to fear that your important player for next session can't show, because you can fill the time with your side story. It gives the players something cool to do, and a chance to shine while being one down. It gives you something to run without having to de-rail your current plot. Really, it is a good fix all around.
Any thoughts on this? Anecdotes of you pulling it off particularly well, or poorly? Fun side stories that turned into major plot development later on when the PCs kept bringing it back up? (always a fun occurrence btw)