I've got these two old friends, maybe from school, now in their early 30s living in a flat in London. The first part of the story sees these two reverse roles. The settled one, we'll call her Alpha, loses control over a few things in her life and ends up needing help from the restless one. The restless one, we'll call Beta, through helping her friend, sorts a few things out.
The Middle ?
So now I'm at this role reversal. But why is it interesting? How can this situation be used to produce conflict? Should some crisis happen that Alpha used to take care of but in her new found chaos, it's up to Beta? Also, due to this reversal, we've got some resentment simmering. The roles they had in respect to each other has been disturbed so that their friendship doesn't really work any more, though on the surface it's still ticking along. How could this be interesting? Should one need the help of the other? - but that would be a repeated plot point.
I already know the end. We work out why that resentment developed, map it back to things in the past. Ultimately the two women have to work out a new way of relating to each other because their lives have changed and they have changed. It's something that does happen in longterm friendships and I know how to play that out - it all ties back to why Alpha needed Beta's help in the first place.
But I'm stuck in the middle. I need a plot filler. An ex-boyfriend. A crisis. A practical problem - a mouse in the kitchen / an alien spaceship in the back garden.