Fangirl is a novel aimed at young adult readers, but it is also entertaining and thought-provoking for adult readers too. It is the story of Cather Avery, whose mother left her twin sister Wren and herself when they were eight years old. Traumatized, and reacting to this trauma differently - Wren acting out, Cath turning inward - they seek solace in a childhood obsession with fictional wizard Simon Snow. For Cath, this obsession becomes her life. She is a success in the world of fan fiction writing in a way she has never been in real life, and would remain lost in a fictional world if she could because the real world frightens her. Now as the twins embark on college, Wren decides that she wants independence and does not want to share a room or spend much time together. Cath is devastated and stressed about her situation with a confident, hardly-there room-mate, a crush on her room-mate's boyfriend, and a bipolar father who is not taking proper care of himself now his daughters are not at home. The novel follows Cath through her first year of college where she surprisingly prevails as the high-achieving twin and emerges with a best friend, a boyfriend and an essay published in the prestigious Prairie Schooner.
Author Rainbow Rowell was inspired to write this novel after reading a great deal of fan fiction which re-shapes the way she wrote novels and particularly the way in which she understood her own fictional characters, making them creatures with many possibilities and outcomes, not just the ones that she writes about. Her first book, Eleanor and Park, was published to great acclaim, and her basing her characters in the area in which she and her family live makes them seem more real-life than fictional.