on Helping Writers become Authors:
In medias resis the useful but sometimes tricky writing technique of beginning your story “in the middle” of things.
At its most basic, this is simply a solid reminder to begin your story with something happening.
This might be action in the traditional sense, but it might also just be the character moving toward a scene goal.
However, in medias res can cause confusion for writers who feel pushed to either manufacture action for their opening scene and/or open late in the story in a way that compromises the structural timing.