When students of literature are asked to identify elements of a novel or short story, they’re pressed to pinpoint what the story is about.
They could answer with plot details, something about the actions of the characters.
However, they could also go for a behind-the-plot meaning, something less about events and more about significance, perhaps even a conclusion they’ve drawn from the book.
I’m talking about theme.
Plot is the events of story; theme is the meaning behind or revealed by story. See More . . .