Although natural disaster might spring to mind as the likely candidate for this plot scenario, disaster plots are actually concerned with the fall from power. This makes it an excellent scenario for plot-driven stories. You can check out some of the other scenarios here.
- A vanquished power is informed of defeat by victorious enemy or messenger.
The simplicity of the disaster plot makes it easy to slide characters in as necessary. Your vanquished power can be either antagonist or protagonist. You’ve also got the option of including both the victorious enemy and the messenger, or only one of the two. The choice is strictly yours, and again, allows you the room to have the protagonist or the antagonist in either position.
As a main plot, this works well for plot-driven stories, with little need or room for character development. This may mean you need to take care and build out your back stories for your characters.
For a minor plot, disaster can help tie up character arcs, especially those concerned with a fall from grace or similar changes.
Although this is drives plot forward, disaster as a scenario can help with character building and arcs.