Why is the play happening now? Or even more succinctly, why now? My friend, the fabulously talented dramaturg Lenora Inez Brown, aptly names it the Passover Question. But whatever you want to call it, you'd better come up with a good answer.
Plays begin at some particular moment in the characters' lives. So why did you choose the one you did? Why not last week? Or last month? Or why not next year sometime? Usually, it's because something has changed. Maybe some event has brought an entire family together. Or a character has lost his job or been kicked out of school.
In my play After Math, the play begins because Emmett has disappeared. In Tiny Tim Runs the Marathon (aka Run Like the Dickens), the discovery of Tiny Tim's discarded crutches and his announcement that he's in training to run the marathon causes the play. In Vital Organs, a transplant patient is imminently being kicked out of the hospital. What do all of these situations have in common? In each case, something has disrupted how things usually are (aka "the status quo").
So when I ask you "why now?" about your play, what will your answer be?