This film isn't really all about Lily Chou-Chou, a fictional Asian pop star with a rabid following to rival Björk's, but about two of her fans: a pair of junior high school boys in a depressed, semi-rural district in Japan.
The story follows two years of the boys' lives and is divided into three sections: the first follows the growth of the boys' friendship as they bond over music, computers and their own loneliness. (Both are harassed by the school's predatory in-crowd.) The central section of the film is an extended home video-style document of the nightmarish vacation the boys take with their friends in Okinawa. The third part depicts the breakdown of their friendship during their second year in junior high, when the social order abruptly changes and one of the boys rises to the top, reinventing himself as a sadistic pimp.
As with a lot of contemporary Japanese cinema, you've got enough rape, murder, and suicide in the mix to balance the story on the line between being a disturbing look at teen life in Japan and being an overly melodramatic examination of classroom politics. In the middle of it all, we are treated to random text messages on the screen, taken from online chatrooms in which the boys, and other fans, ramble on and on about their beloved Lily.
All About Lily Chou-Chou is beautifully shot, with wholly believable performances by its young cast, but it's so stone cold serious that even if you accept it as an honest portrait of Japanese teenagers, its point of view is too hopeless to fully admire. Still, it's affecting and worth a look.