Erika (Isabelle Huppert) is a piano professor at a Vienna music conservatory, living with her overbearing bitch of a mother (Annie Girardot) whom she both loves and hates, whose father is in a mental institution, and who, despite her conservative exterior, harbors an unparalleled repressed sadomasochistic sexual appetite inside her. This combination of factors has rendered her a bit on the irritable side, and she takes this out on her students by subjecting them to ruthless criticism.
At a recital one night, Erika meets prospectless engineering student Walter (Benoît Magimel). Though it takes a long time, and despite the fact that by all appearances they cannot stand the sight of one another, the two eventually become romantically involved, behind Erika's mother's back.
This film provides examples of:
- Adult Fear: Despite her tendency to be a smotherer, Erika's mother is rightfully concerned when Walter barges in at the end of the film and locks her in a storage room, leaving her unable to help as he assaults her daughter.
- Anguished Declaration of Love: After being rebuffed by Walter when he reads the letter, Erika attempts to do one of these at his hockey practice, telling him that she loves him and will let him do whatever he wants to her.
- Be Careful What You Wish For: Erika repeatedly toys with Walter, appearing to give in to his advances before crudely rebuffing him. This all culminates in a letter she writes to him, wherein she asks him to assault, tie up and humiliate her. He ends up following her wishes to a T — locking her mother in a storage room, beating and then raping her.
- Bookends: The movie start and ends with Erika walking through a door.
- Clingy Jealous Girl: When Erika sees Walter flirting with one of her students, she breaks a glass and puts the shards in the student's coat pocket so she cuts her hands and can never play piano again. She stops just short of being a complete Yandere.
- Crippling the Competition: Erika is enraged at the sight of Walter flirting with one of her students that she goes so far as to fill the pockets of the girl's jacket with glass while it's in the cloakroom. The moment the poor student habitually jams her hands in her pockets, she's promptly cut to ribbons, preventing her from playing at an upcoming concert and giving Anna a chance to substitute.
- Drive-In Theater: Erika follows Walter into one of these where she turns into The Peeping Tom.
- Elder Abuse: Walter shoves Erika's mother into a storage closet not once, but twice, with the first showing him practically throwing her into the room. She's then forced to listen helplessly as he assaults Erika.
- Exact Words: When Walter confronts Erika in the apartment near the end of the film.Walter: "Give me lots of slaps, darling. Hit me hard..." (Beat) "Hit me around the face and hit me hard." At your service, dear lady. (slaps Erika)
- I Kiss Your Hand: Walter displays some Old-School Chivalry when kissing Erika's hand on their first encounter.
- Jerkass: Erika comes off as this quite a lot of the time. See above.
- Job Title: The movie title describes Erika's profession.
- Kinky Cuffs: Shown as part of the stash of items Erika keeps under her bed, along with rope, chains and other assorted bondage gear.
- My Beloved Smother: Erika, aged around 40, is still single and living with her mother.
- No Ending: The film ends without answering the resolve of Erika and Walter's relationship, and also not showing the aftermath of the concert Erika leaves behind.
- Parental Incest: In a state of confusion and repression after Walter reads the letter and rejects her, Erika climbs on top of her mother in bed and kisses her, leading the latter to freak out and tell her daughter to stop acting like a lunatic.
- Playing Sick: When Walter asks if he can kiss Erika on the neck, she fakes a coughing fit in order to get away for a moment. She does the same thing a few seconds later when he asks her to go on a weekend getaway with him.
- Reality Has No Soundtrack: As usual with Haneke, all sound heard in the film is performed in-universe.
- Self-Harm: Erika stabs herself in the shoulder/upper chest area at the end of the film, possibly in an attempt to feel something after witnessing Walter walk off smiling with his family at the piano recital.
- Sick and Wrong: Erika forces Walter to read her letter out loud, which lists graphic depictions of sexual acts she wants him to do to her. His reaction after finishing the letter is this (and plenty of disbelieving looks), coupled with her "Not Making This Up" Disclaimer.
- Silent Credits: Opening and closing credits roll in silence.
- Sounding It Out: Walter reads Erika's letter out aloud to let the audience know of its content.
- Vomit Indiscretion Shot: Erika's fellatio on Walter ends with her puking on the ground.
- Would Hit a Girl: Erika's sick fantasies bring out the worst in Walter and he starts to hit her vigorously.