Essentially and most simply put, plot is what the characters do to deal with the situation they are in. It is a logical sequence of events that grow from an initial incident that alters the status quo of the characters.
“We do have a problem in this country. You can either make a movie and ignore that, or you can acknowledge it and say, this is the water that we're living in. You know this - the movie lives in this - it's centered around this particular problem, and I chose to acknowledge it.”