Overture - 

noun
1. an opening or initiating move toward negotiations, a new relationship, an agreement, etc.; a formal or informal proposal or offer:
overtures of peace; a shy man who rarely made overtures of friendship.
2. Music. an orchestral composition forming the prelude or introduction to an opera, oratorio, etc.
an independent piece of similar character.

3. an introductory part, as of a poem; prelude; prologue.
4. the action of an ecclesiastical court in submitting a question or proposal to presbyteries.
the proposal or question so submitted.

entr'acte 

n
1. (Theatre) an interval between two acts of a play or opera
2. (Theatre) (esp formerly) an entertainment during an interval, 

such as dancing between acts of an opera
[C19: French, literally: between-act]

finale
noun

the last part of a piece of music, an entertainment, or a public event, especially when particularly dramatic or exciting.
"the finale of Beethoven's Ninth Symphony"

synonyms: climax, culmination; 
end, ending, finish, close, conclusion, termination, resolution;
denouement, last act, final scene, final curtain, epilogue, coda, peroration; 
informalwind-up
"the work ends with an elaborate finale"

In medias res, ( Latin: “in the midst of things”) the practice of beginning an epic or other narrative by plunging into a crucial situation that is part of a related chain of events; the situation is an extension of previous events and will be developed in later action. The narrative then goes directly forward, and exposition of earlier events is supplied by flashbacks.

The principle of in medias res is based on the practice of Homer in the Iliad and the Odyssey. The Iliad, for example, begins dramatically with the quarrel between Achilles and Agamemnon during the Trojan War. In his Ars poetica, the Latin poet and critic Horace pointed out the immediate interest created by this opening in contrast to beginning the story ab ovo (“from the egg”)—i.e., from the birth of Achilles, which is the story’s earliest chronological point. Though its roots are in ancient epic poems, in medias res can be found today across numerous fiction and nonfiction narrative forms. (Source: Encyclopedia Britannica)

Pathetic fallacy is a literary device that attributes human qualities and emotions to inanimate objects of nature. The word “pathetic” in the term is not used in the derogatory sense of being miserable; rather, here, it stands for “imparting emotions to something else”.