She is "Kimmie's little sister" and Kimmie is off to college. Her aunt tells her that an old friend is coming to spend the summer. He is given Kimmie's room and he finds Muffy's diary and we're shown what it contains via flashbacks.
Sharon Mitchell
Director
Heather Wayne
Little Muffy Johnson
Karen Summer
Rhonda
Misty Regan
Kate
Marc Wallice
Douglas
Ted Wilson
Karl
Tony Martino
Neil
Billy Dee
Love & Sex61%
Xiu Xiu: The Sent-Down Girl72%
The Diary of a Teenage Girl65%
The Substance71%
Pimp62%
Room 23761%
Unthinkable68%
The War Zone68%
The Doors71%
Heavy Metal 200060%
The Clique59%
Trainspotting79%
Pretty Persuasion58%
For Sama82%
Repo Men63%
The Substitute 2: School's Out63%
The Collection63%
Total Recall73%
...All the Marbles61%
London60%
