Plot Device: Foreshadowing...!

Foreshadowing is when the opening scene of a story

acts as a kind of nutshell prophecy for the whole story.


In a Horror, this is when the originating Bad Thing happens.
In a Mystery or Crime story, it's when the first victim is slain, and/or object (McGuffin) goes missing.  
In a Romance this is where the main character meets their soon-to-be lover for a fleeting but memorable moment.