In medias res, (Latin: “in the midst of things”) the practice of beginning an epic or other narrative by plunging into a crucial situation that is part of a related chain of events; the situation is an extension of previous events and will be developed in later action. The narrative then goes directly forward, and exposition of earlier events is supplied by flashbacks.

The principle of in medias res is based on the practice of Homer in the Iliad and the Odyssey. The Iliad, for example, begins dramatically with the quarrel between Achilles and Agamemnon during the Trojan War. In his Ars poetica, the Latin poet and critic Horace pointed out the immediate interest created by this opening in contrast to beginning the story ab ovo (“from the egg”)—i.e., from the birth of Achilles, which is the story’s earliest chronological point. Though its roots are in ancient epic poems, in medias res can be found today across numerous fiction and nonfiction narrative forms.