On Agate Hill is set in North Carolina in the years from 1872 to1927, and also in the present. The novel evokes the South in Reconstruction from an honest female perspective. It is the exuberantly romantic and episodic story of Molly Petree, an open-hearted and headstrong young Southern woman. The novel is framed with the letters and notes of a contemporary woman who seems almost a reincarnation of Molly herself.