The deep, dark waters of the lake ...

This is one of my more current books, based on the Arthurian legends. It's one of the Remembered Classics, in which I take some familiar characters and re-imagine them.
I always wondered about Vivian, the Lady of the Lake. The babe who tossed out a sword and decided who would be king. I started thinking about her and wondered, what if a woman had a lake home but she was terrified of deep water?
I started working backwards: why is she terrified of water? Has she always had a lake home? How would she meet the owner of the sword? What kind of business does she have that puts her in the way of a sword?
And then there was him: how did he lose the sword? What's his blind spot? What does he do for a living? How does he find?
Somehow, a book came together, in which Vivian comes into possession of a sword that Able (Arthur Baer LeRoy) is seeking. But is Arthur who he says he is? What does Vivian's ex-husband have to do with it?
Plus, there's that lake and her cabin ... and a cold October day when things get really terrifying.