"Good Girl Gone Plaid" is a coming-of-age story that follows the shenanigans of a young Catholic school girl, Riley Patton, who ensures that humor and wit drive her daily desire to do what is good. Unfortunately, Riley continues to find herself in constant trouble with the nuns who preside over the school and at home with a mother who favors her two other sisters, leaving Riley feeling abandoned and hurt.

Riley finds relief in tomboy adventures like poaching frogs and skinning fish with her best friends, and in writing in her "plaid/sad/mad/glad Father God and Mother Mary" journal. While she loves writing as well as anything related to sports, Riley struggles to find the "girly girl" within, comparing herself to others and hoping to get the boy of her dreams. She realizes, however, that her dreams lie not within others, but in discovering who she is and her own desires for her life, which may not always include boys.

As a fifth grader, trouble follows Riley home as well, where she negotiates her way through the battles that belie a big middle class Catholic family of seven including her four siblings. Riley is a sensitive young girl who is both brave and curious, to her own detriment at times. She fights for the causes she believes to be true and fair and her self-confidence is won only by risking to be who she truly is.