Back to play beginnings. Let's look at A Streetcar Named Desire.
Setting: Elysian Fields, New Orleans, late 1940s. (I think the play was contemporary in its day.)
Situation: the neighbourhood is poor; money matters. Men rule. The atmosphere is combustible, disorienting. It's hard for people to know how to make their way in life.
Catalyst: Blanche DuBois enters.
The rest is theatrical history. All this, by the way, in the first three pages. I said that the catalyst presents the central character with a problem, and creates a goal for her or him. In this case, the catalyst also introduces the central character. Simply walking into this world is a problem for her; survival becomes her goal. (Williams will eventually give her another, more specific, short-term goal.)
Cloud 9
Setting: Africa, late 19th-century.
Situation: Colonial Africa. Displaced British aristocrats are showing the flag. They are comically out of place. God, country, patriarchy rule. In pure theatrical terms, the fact that Betty is played by a man is probably part of the situation; it suggests that, beneath the surface, all is not quite so neat and clear. At any rate: she's bored.
Catalyst: the news that Harry Bagley, explorer and heavy drinker, is about to arrive.
And Cloud 9 is not at all a conventional play.
To Toot 9