OK, so what's the mystery? A novel about a princess story? That's right. The princess story is written in SecondLife by Babu Writer. When that is done, the real person behind the avatar will stand up and complete the real story of the novel.
The protagonist in the novel is none other than Babu Writer herself, a writer of children's stories. She has written the story of The Lemon Princess for a child, her child. We hear this child's voice, asking questions. Babu answers. The pair has a close relationship. But where is the child? Why do we never see her? Is she a ghost? Did she ever really exist? Is she a figment of the imagination? Why is she haunting Babu? Why does this tale grow increasingly dark, even as the story of The Lemon Princess grows cheerful and bright?
You will have to read the novel to find out.