See Laconic. Basically any stock plot that essentially follows this scheme - For vague reasons, everything is running smoothly and people are happy. How or why things got this way needn't be explained. And then They come, which forces the heroes into action.
Sometimes They are actually named. They can be either aliens, foreigners, or demons. Once They come there is more room for fleshing out who They are, They might tell you what They are doing, and if you're lucky you might even find out where They came from. But the point is any extra details can be superfluous
and sometimes the stories thrives on the ambiguity of They.
The important thing is that before They came things were good, now things are bad, and now They must be dealt with.
Related to Vagueness Is Coming
(future oriented), or War Was Beginning
(In Media Res
- present tense), but Then They Came
is more about past events. Like its sister tropes, commonly advertising, trailers and prologues as its a easy way to get audiences head around the main plot. Sometimes used in story during flashbacks and explanations. A quick fix to introduce the Evil Army.
They usually end up bringing about the End of an Age
, that causing survivors and storytellers to muse about how life was Before The Dark Times
. See also You Know The One
For more specific types of who They might be compare Alien Invasion
, The War of Earthly Aggression
and The Dragons Come Back
- The War of the Worlds has the people of England going about their daily business, and then one day Martians show up and heat ray the dogshit out of a small town and the surrounding countryside. The martians prefab together some tripod mecha and take over, and then they drop dead of a cold within a week.
- In YA lit, there is How I Live Now, where the invaders aren't even identified.
- Justice League, Martian Manhunter describes the history of how the martians went extinct this way in the first episode.
- Avatar: The Last Airbender: Katara introduces the concept of the war this way in the opening, "Long ago the four nations used to live together in harmony, then everything changed when the Fire Nation attacked.' The first season plays it straight and keeps the villains simple. The final season had an episode dedicated to examining the who, what, where, when, and why behind that attack.
- In real-life the Shashu and Habiru peoples who may or may not have been the ancient hebrews. to this day nobody knows who they were really but Egypt complained about them sacking their lands and causing trouble in parts of the levant. Also the Monguls when they first showed up.