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-public.
They can only be kept awake by “and then—and then—”
They can only supply curiosity.
But a plot demands intelligence and memory also. (70-71)
Forester also suggests that the writer consider the "demand [an element] makes on the reader. Curiosity for the story, human feelings and a sense of values for the characters, intelligence and memory for the plot" (92).
Forster, E. M. Aspects of the Novel. books.google.com. 2012. Google Books. Web. 20 Aug. 2012.