October Novel Prep Challenge

I've hit a common barrier for me, the one that stops me completing anything much that I plan. I have a start, and I have an ending, but the middle is empty. A bit like custard creams without the custard!

I have been What-ifing (is that a term? It is now) though that is easier with someone to bounce off. (My eldest son and I have been brainstorming a story about an immortal Artificial Intelligence this week and that was a lot of fun). No joy. I have a character with not much to do and no sub plots. It's getting a bit depressing.