I have my main characters' names, Hilda and Justice, so that if I have to, I can title it Hilda and Justice, although I'd rather not. And I know how they're going to play off each other, and what they want (or think they want)--but I don't know WHY.
Why why why whywhywhy? Why does Hilda want terrible revenge against the guy I haven't invented yet? Why is Justice living on the outskirts of the drake colony after being brought all the way to the city at great expense? Why can't I dredge up anything except the most banal of plot points?
Ice cream might help. Ice cream, or a really long walk around town so I can think. And then ice cream.