First-year junior high students Mai and Miyuki naturally huddle together during their transitional year from classmates of elementary school. Once in their more metropolitan junior high school, however, they are soon introduced to a wider and more exciting exposure to the world.
On the positive side, this includes independent ventures into the more culturally notorious elements of Tokyo such as Harajuku with slightly drunken upperclassmen (BOYS!!). Unfortunately it also involves being thoroughly initiated into their new school's rumored history of an omen-filled death three years prior on the school's rooftop and stories of hauntings by the ghost of a young girl.
The upperclassmen enthusiastically discuss these things nightly via a web bulletin board (BBS) where eventually the rumor emerges that the school-bound ghoulie Hanako is released from her confines if and when a particular mirror in the school is broken. And sure enough, when the school if horrifically vandalized, Miyuki sees a young girl in an outdated school uniform wander from the school grounds.
And then very strange and terrible things begin happening on and off campus. Students meet bizarre demises on there way home and the school itself beings to crumble in a flood of uncontrollable mold. When a student posts a malicious message on the internet bulletin board suggesting that a "new Hanako" should replace the former, the frenzied panic takes on its own malevolent momentum.