I remember seeing this when I was in high school back in 1973. What a great introductory role for Stockard Channing - it really played to her strengths. Miriam (Stockard Channing) is a homely girl, about age 21, who has been changing colleges every semester because of how she is ignored at best, tormented at worst, at every turn. She's very smart and very talented, but every time she tries to turn over a new leaf it's the same old story. At her new school she's the butt of a joke in which the school jock takes her on a fake date just to humiliate her, and then she gets the leading role in a play stepping ahead of her cheerleader dorm roommate. She is humiliated there too because the roommate takes revenge by making sure the bouquet she gets as part of the play are roses - Miriam is allergic to them. Miriam goes into a sneezing fit, cannot say her lines because of it, and runs off the stage crying with the whole audience laughing at her performance. Driving away and in tears she has a disfiguring automobile accident. Laying there in the hospital she receives the final insult - her long-time reluctant pseudo-boyfriend Herman tells her he is marrying someone else.
However, this is where Miriam's luck changes. Plastic surgery completely changes her appearance and makes her beautiful. Now that she is beautiful, unrecognizable, and still smart and talented she goes on a homicidal tirade of revenge against all who wronged her - at least the ones we know about from the film, that is. Ironically, she doesn't actually lay a finger on any of them. Furthermore she uses her tormentors' own vanities to send them to their deaths. Technically, though, it is murder, so Edward Asner, as a homicide detective, tries to fit the pieces together and pretty soon he finds he's falling in love with the murderess' mind - he has no idea what she looks like.
Joan Rivers wrote this little gem, and if you know anything about her style of comedy and the burgeoning women's lib movement in the early 70's, this film seems to not so much come out of nowhere. Whenever I think of this film today, I always think about the fact that America's most popular TV show "American Idol" does exactly what drove Miriam over the edge - put less than attractive people center stage so people can feel better about themselves by laughing at them.