Free software for writers

StorYBook is a free, summary-based open source software for creative
writers, novelists and authors that helps to keep the overview over
the strands while writing a book, a novel or a story. StorYBook
assists you in structuring your book.

StorYBook is a tool for managing meta data like chapter summaries,
characters and locations about a novel. It is not a replacement for a
word processing software.

http://storybook.intertec.ch/en/