The book focuses more on Mrs. Claus rather than on Santa. It is about Mrs. Claus being put in a situation where Santa becomes ill, and she is placed out of her comfort zone so that children won't be disappointed for Christmas.
I got the idea while watching Christmas cartoons this past year, and I noticed that we really weren't seeing Mrs. Claus. I'm old-fashioned, and I don't like computers, so I picked up a pencil and eraser at first when I began writing.