So perhaps you have decided to participate in Nanowrimo. The next thing that your thinking is what now?
This is the time to prepare, outline, characters and plot. You can either plan or you can fly by your pants.
Some will prefer to use detailed outlines. Others not as much.
Maybe right now all you have a vague notion. A sentence beginning with those iconic words What If?
All you need right now is the rest of the question. This is your starting point.