When I have to tell someone in a particular TV series for example Dragon Ball Z. "Let me tell you the plot of the story arc of those episodes when Goku fights Vegeta."
The simplest way of explaining it is "story arc" is a completely meaningless phrase, and I, for one, haven't the least idea what it is supposed to mean.
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.