You know what they say: "on the surface, everything seemed fine, but below the surface - there's another story."
Looking below the surface, then, is similar with "reading between the lines" to get to the essence. Don't interpret everything literally - appearances deceive...
The audience is taken for an (adventurous) ride - through the landscape of the story. They are inside the plot, and yet passive spectators of the show unfolding before them.
The audience is trying to get ahead of the plot, i.e. to be one step ahead of everything happening in it, and based on what they know figure out the end of the story, long before it's over.
Student or Learner