A story is a narrative of events arranged in their time sequence. A story is defined by,” and then, and then, and then.” The king died and then the queen died. That is a story.
The king died, and then the queen died of grief. That is the plot. The plot maintains the time sequence but now the emphasis is on causality.
In the story, we ask,”What will happen next?” The story appeals only to that most basic of human faculties; our curiosity.
In the plot, we ask,” why?” So the plot requires not just curiosity, but also intelligence and memory. There must be mystery in a plot.