Your sentences are better without the phrase "the story arc."
He told me the plots of the first six episodes of GOT.
Let me tell you what happened in those episodes.
Let me tell you the plot from that series.
If you're simply trying to explain the plot of a show or series to a friend, there's no reason to use a fancy term like "story arc" anyway. And I don't think it's correct to refer to a story arc as having a plot.