Crimes are a villain staple. Bank robbery, arson, kidnapping, and the ever-popular holding the city for ransom – it’s what villains do.
But in games there are really only two kinds of crimes: those where the specific crime matters (plot), and those where the crime is just a setting for the action (premise).
A classic bank robbery scenario is just an excuse to let the heroes go after the villains. You could easily substitute a jewelry store robbery, a scheme to steal mint plates, a kidnapping, etc. Either way, the bad guys are trying to do something and that brings the heroes running: trouble ensues. The crime is a premise for the action.
On the other hand, the specifics of the crime are important if they affect future events. It matters that the villains are trying to steal a prototype laser if they are going to use it to knock out a satellite in the next scene. Heroes still rush to the scene of the crime and pound the villains, but whether the heroes know it or not, the crime is a key point of the plot, not just an excuse for the action.
– Robbing a bank for money? Premise for action. Robbing a bank because there is something hidden in a safe deposit box you want? Plot.
– Kidnapping the mayor and holding him for ransom? Premise for action. Kidnapping the mayor because you want to replace him with a synthoid replicant? Plot.
– Setting fire to the tenements so you can watch this city burn, burn! Premise for action. Setting fire to the tenements to create a fiery gateway for your demonic overlord? Plot.
Here’s a simple test: in a later scene, will there be a moment when the heroes should look back and say, “a ha! That’s why they did that crime! It all makes sense now”? If yes, it’s plot. If not, it’s a premise for action.
Just committing a crime to get money is not specific enough to be plot. There are lots of different crimes that result in profit but are basically interchangeable, even if the heroes later realize the villains wanted all that cash to put a down payment on a really big group house.
A crime that’s a premise for the action is not better or worse than one that is part of the plot. They’re just different building blocks of a scenario, but it is important to understand which you are using when you are running a game.
–excerpt from Evil Genius #2: Crime & Punishment
(And yes, plot vs premise for action is really a much bigger idea that applies to just about everything that happens in your game. Everything is plot or premise. Crime scenarios are just one easy example.)