The novel details the lives of Tom and Maggie Tulliver, a brother and sister growing up on the fictional river Floss near the fictional village of St. Oggs, after the Napoleonic Wars but prior to the first Reform Bill in 1832. Spanning the years from Tom and Maggie's childhood up until their deaths in a river flood, the book is loosely autobiographical and reflects the disgrace that the author herself faced while in a relationship with a married man.