Before you write a single line of your script

Before writing a screenplay that a film will be based on, you must solve a few key issues.

The film must be about something, have a theme.
It can deal with, for example, the moral state of a society or a social group.
You must have something to communicate to the viewers.

Even comedies should leave the audience with something to think about -
How would I behave in such a situation?
That's the best kind of learning - throw the viewer and the hero into a difficult moral situation,
let them ponder, then show how the hero copes (or fails).

The viewer should experience it alongside the hero, learning something about themselves.

Screenwriters, like journalists, have a huge influence on their audience.
That's why it's such a responsible job, especially when writing for young people whose worldview is still forming.
Teaching that evil is good can backfire - one day that person might be your boss, a politician, or someone you meet in a dark alley.

This doesn't mean the hero must be perfect - but they should go through a character arc, realizing that evil lingers and saddens, while goodness returns to you.