Miss Brodie is a teacher, a formidable figure who molds young minds to her form. And what is more, she is so intensely interesting that the girls admire her above all else. But Miss Brodie is not honest. She prevaricates and then tells the girls to do as she tells them, not as she does herself. She is having an affair with the music teacher and has had one with the art teacher, and this is not the most exemplary conduct.

A fantastic letter which some of her students write in her name to her lover falls into the headmistress' hands. Dismissal is averted by Miss Brodie's indomitable pluck as she threatens to sue for libel. One girl grows too wise too soon and turns on Miss Brodie.