You may be asking what is the difference? Simply put, the theme is what the story is about (coming of age, overcoming fear, etc.). The plot is what happens to reveal the theme.
In every good story, plot will eventually reveal theme. But the two are not the same. It is important to understand this when describing your story, whether to an agent, an editor, or another writer.
Plot is what keeps your story moving forward. It is the series of events that keep your reader turning pages. Plot is action, whether internal or external.
So, the next time someone asks you what your story is about, give them the plot. Nothing but the plot.
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