Hints inserted by the author to indicate to the careful reader how the action is going to develop, and thus to contribute to the credibility of the plot
A literary device in which an author drops subtle hints about plot developments to come later in the story
When later developments in a narrative are hinted at early on The famous Pushkin law--"Never plant a gun in the first act unless you intend to use it in the last"--is really about foreshadowing