Thanks for your question! I had the basic plot and cast in mind from the start--I knew, for example, that Lydia would be dead and that she'd drowned in the lake, and I had a basic idea of why. And I knew the major things that had happened in the family's history. Those actually stayed pretty constant throughout all of the drafts and all the writing. But as I wrote, I figured out *why* those events had happened, and learned much more about each of the characters. For me, writing is always a mix of what I know (or think I know) and what I don't know, of exploration and explanation.