The book follows the sibling rivalry between a sister (age 8; third grade) and her younger brother (age 6; first grade). The book is divided into two parts, each told from the viewpoint of one sibling.[1] The girl refers to her brother as "The Pain," due to him always being a nuisance to her, while the boy calls his sister "The Great One," a sarcastic nickname based on her thinking herself the better sibling. It is a humorous look at the mixture of emotions shared by young siblings.
On the last page of each section, the sibling narrates the line, "And Daddy says, 'The Pain/the Great One is just what they always wanted'. YUCK! I think they love him/her better than me!".
Years later, between 2007 and 2009, Blume published four additional books featuring these characters; they are not picture books.