Generally speaking, when we speak of a story’s plot, we are speaking of “the sequence of events” that comprise the tale. Some will quibble about this definition, but it’s the most common understanding of the term.
And most of us remember being taught the basics of plot structure via a witch’s hat plot diagram like this:
At about the 20 percent point of the story, corresponding to the end of Act I in the three-act drama structure, there’s the First Reversal. Something happens to transform the Hero’s new situation into a new desire and a change of plans. This will set the Hero’s external motivation for the rest of the novel, and the action is underway.