Plot in a work of fiction is the movement of the story through its narration—A famous piece of scholarship on Shakespeare is called “What Happens in Hamlet?”  That is the essence of what is meant by the term.  One convenient and fruitful taxonomy splits plot into three “movements”—outward, inward, and static (status-confirming).  What this division does is stress the fact that plots move.  A Bildungsroman is an example of a plot that moves outward (Catcher in the Rye, Stephen Hero, etc.)  A young person at the beginning of the novel is inexperienced, naïve, and innocent; then events in his life move him toward maturity, understanding, and experience.  This is an outward, upward movement of the plot.  An inward plot drives the main character(s) inward, to self-examination, discovery, reconciliation with his inner conflicts; Hermann Hesse’s Glass Bead Game, Mann’s Magic Mountain ).  The third kind of plot, often a portrait of a society more than characters, establishes a mise-en-scene and then confirms it by moving a character through the social environment, usually as a “victim” or someone absorbed by thr environment (Hardy’s Tess of the D’ubervilles, Fitzgerald’s The Great Gatsby, all of Balzac).  Of course, there are other ways of dividing plots—by their main character’s control over the environment, for example).