It wasn't plot, character, or setting. It's the dynamic. It's how the characters will end up talking to each other. It's a little like banter, but with substance.
I looked over the thread a bit and I got the feeling you two (Devor and FifthView ) are talking about different things - while using the same word.A dynamic situation. Constant changes. A world alive, and a character just as alive—This description might approach that feeling of dynamic I'm now experiencing.
...and then Devor comes along and posts something just as I'm typing.
Maybe that's what I'm thinking of when I wrote that the ideas reach critical mass and turn into a story. At some point I get to a stage where I can tell whether adding something to the story will work or not.