In medias res

In medias res is a fancy way of saying that when a story starts, it doesn't always start at the very beginning. Instead, it starts right in the middle of the action. Imagine you are playing with your toys and suddenly your mom comes in and says, "Hurry up, we have to leave to go to the store right now!" That's in medias res because you weren't expecting it, and it starts the story right in the middle of something happening. This is a way for writers to grab your attention and make you interested in what's going on right away.