In Medias Res:
beginning a narrative in the middle of the action. Often this technique will be accompanied by flashback or dialogue that explains what has gone before. (May be used in the narrative essay)


Example:
 "He saw the townlands and learned the minds of many distant men, and weathered many bitter nights and days in his deep heart at sea, while he fought only to save his life, to bring his shipmates home.
But not by will nor valor could he save them, for their own recklessness destroyed them all." -The Odyssey


Explanation:
The opening lines of the Odyssey start in the middle of a small amount of action. It is not violent, but is in the middle of a scene, that we have no knowledge about. The reader has to wonder why they have been at sea for a long time, and why they are fighting to stay alive due to their own recklessness. Starting a scene in the middle of  "action" allows the reader to foreshadow and suspect what will happen later in the novel, which is what the author wants. It builds suspense and mystery, and makes the reader want to read more. Homer also does this so he can create flashbacks later on in the novel, which makes it more dramatic.