 Thornhill's son, Dick, leaves him to live with Blackwood, and Thornhill's friendship with Blackwood also deteriorates, which leads Thornhill to have a sense of guilt of his actions.Grenville followed up "The Secret River" with a non-fiction book titled "Searching for the Secret River" in which she describes both the research she undertook into the history behind the book and her writing process.She chronicles how she changed from her original plan of writing a non-fiction book about her great-great-great-grandfather, Solomon Wiseman, to writing a fictional work.