“Let us define plot. We have defined a story as a narrative of events arranged in their time-sequence. A plot is also a narrative of events, the emphasis falling on causality. “The king died, and then the queen died” is a story. “The king died, and then the queen died of grief” is a plot. The time-sequence is preserved, but the sense of causality overshadows it. Or again: “The queen died, no one knew why, until it was discovered that it was through grief at the death of the king.” This is a plot with a mystery in it, a form capable of high development. It suspends the time-sequence, it moves as far away from the story as its limitations will allow. Consider the death of the queen. If it is in a story we say “and then?” If it is in a plot we ask “why?” That is the fundamental difference between these two aspects of the novel. A plot cannot be told to a gaping audience of cave-men or to a tyrannical sultan or to their modern descendant the movie-piblic. They can only be kept awake by “and then—and then—” They can only supply curiosity. But a plot demands intelligence and memory also. — E. M. Forster, from Aspects of the Novel
MARTHA McPHEE 
Great post. He makes it seem so simple, which I guess it is in the end. But getting there is so much work! I recently read A Passage to India which has some of the simplest but most satisfying plot twists in literature.