I don't necessarily mean a fight scene/a chase/alien invasion/and countless others. But it has to drive the story forward.
This might seem obvious, but my Muse managed to miss the point. I'm due to write chapter 22 (and will do after this post). I knew what I wanted to happen. I needed Safiya (FMC) to chat to Abidah (secondary character) about what's going on. Originally Muse said they would chat amicably. But on the way into work today I discovered the problem. The reader knew some of the information already. Recaps are dull and unnecessary. I could have put in one sentence where Safiya mentions she spoke to Abidah about current events. But that wouldn't work.
I needed the reader to be there when Abidah learns what's going on. Her reaction is vital to the story. Abidah's actions as a consequence of learning the truth are vital to the story. So how on earth was I going to solve the problem?
Muse had toyed with the idea of revealing a plot twist in chapter 22, instead of a little later in the novel. I did discuss the option with her, but I pointed out it ruined a few other story lines if I revealed the major twist now. I need that twist nearer the end.
So she got a little grumpy and got thinking. I think there was at least one other suggestion, that I dismissed. At last she managed to figure out how to get the info across in a way that propels the story forward, makes a difference to the story, and creates a lot of conflict for Safiya. Muse is happy. I'm happy.
Correction, Muse will be happy when I've written the chapter so I have to go now, otherwise I'll end up with a sore arm from where Muse pokes me!