Given

 In a play particularly, TV and movies too. one has a script describing all that happens within.  The given circumstances are what we work in/with.

It's what's going on.  We might surmise a bit about before, but we don't know what will happen after.  It is the here and now.  Time may be condensed, events consolidated, yet we move forward.

It is rather like life.  The idea is to make it realistic, no matter the topic.  

In life, we have certainties, though some things are sometimes unclear.  We move forwar because there is always a choice.

In the prolog to The Alamo (1960), a brief history is given.  The last sentence talks of the eternal choice of men: To endure oppression Or to resist.

Let's use what's given to fashion the future.