What do I do when I can't get further than the first chapter in an already planned book? Write another one. It wasn't my fault (you know who you are...!) this new idea. And I'm not even sure it'll be enough of a plot to make any kind of length, but I wrote 10 pages. Way more than poor Morganna has.
I feel bad for her, but what can a writer do? The muse is a fickle, fickle creature.