A couple of years ago, then Pixar storyboard artist Emily Coats tweeted pieces of advice on making stories that she had picked up from working with Pixar, which were later compiled in several places on the internet, such as this io9 post. Later, Dino Ignacio created image macros of the individual rules which I am using in these posts.
Rule #19: “Coincidences to get characters into trouble are great; coincidences to get them out of it are cheating.”
You’ve probably heard variations on the latter part of this rule as advice already if you’ve spent any time reading advice for running games. It’s usually phrased along the lines of “Don’t throw the players into a fight they can’t win and then have your favorite NPC ride in to save them.” Having some help just happen to show up right when the players need it, or throwing the players in jail only for there to happen to be an inmate who is about to execute his escape plan and just needs some help, is a painfully obvious save on your part, and likely to suck all the tension out of the game. This falls into the same category as “fudging the dice” or rolling the dice where the players can’t see and modifying rolls to their benefit. Fudging is less obvious than sending in the cavalry, but over time it’ll have the same effect, because sooner or later the players will, consciously or not, realize that they can’t fail. Of course, as I’ve harped on before, you won’t find yourself as tempted to cheat on the behalf of players if you just make sure that their failure won’t destroy them or unravel your story.
Like most rules, this is one you can break every once in a while if you know what you’re doing and why. In some cases, it may even be genre-appropriate; if you’re running a swashbuckling game along the lines of 7th Sea, it might be entirely appropriate for a player character to survive being thrown off a cliff into the sea thanks to grabbing a branch on their way down and being spotted by a ship that was coincidentally passing through the area. All you have to do to ensure it doesn’t feel like cheating is to make sure that the player doesn’t actually get out of trouble. Sure, they didn’t drown and they probably have some time where their antagonist assumes they are dead, but that ship that just picked them up? Pirates. And they’re either going to try to press-gang the PC into their crew or sell them off as a slave. Instead of the player getting out scot free, they have a new, interesting problem to deal with (this is essentially the fail-forward philosophy).
As for the first part of the rule, when you drill down to the essentials, most plot hooks are coincidences to get players into trouble. The players just happen to be in the right place at the right time (or the wrong place at the wrong time, depending on your perspective) to get sucked into a conflict that they have the skills to handle. This is perfectly fine. In fact, you don’t have to hold back when it comes to getting your players into trouble. Have one of the PC’s turn out to bear a startling resemblance to the prince that’s fleeing from assassins. Decide that the random vampire that they staked in the alleyway was a political kingpin slumming for blood who has now left behind a massive power vacuum. Have a spy steal one of the less tech-savvy PC’s identities to make off with state secrets, so that they have to dodge the CIA while trying to clear their name. In my experience, as long as it fits the genre and tone of your game and gets the players into an interesting story, they’ll happily go along with it. Better yet, if you have a mind to, you can revisit these coincidences later and retroactively make them not. Maybe the reason that PC bears such a startling resemblance to the prince is because they’re twins separated at birth, for instance. The only thing to watch out for is your players feeling like you are strong-arming them into your plots; make sure they have an out, especially if you’re not sure they’ll be into the story you have in mind.
Running a game gives you all sorts of power that can be used to “cheat” the world to keep things running smoothly. Make sure you use your powers in the service of creating interesting stories rather than to recover from failures, whether those failures be your own, or your players’.