Ayami Nakajo, the most popular student at a Catholic all-girls school, suddenly isolates herself in her room. Her admirer, Kasumi Nohara Kasumi Yamaya, kisses her photo at midnight and disappears with her friend Michi Aoi Morikawa as a witness. Her disappearance is quickly attributed to a supposed curse that affects girls who kiss the photo of the person they admire at midnight. Aya’s photo is taken to the attic by Sakuya Itsuki and Risa Fujiko Kojima for safekeeping, but the two alongside three other girls are enticed to kiss the photo. Except for Risa, who is later found dazed but alive, all of them are eventually found dead at a nearby river.
When Michi attempts to kiss the photo, Aya stops her and reveals that she is not responsible for the curse, as the photo is not hers. They seek help in Kazumi “Mary” Kusanagi, an eccentric photographer, who keeps photos inside her studio of lesbian girls who made suicide pact by drowning themselves at a lake, which is now closed down, due to the society’s intolerance toward same-sex couples. She also tells a story about a couple who was doomed when one of them refused to commit suicide, causing her to be haunted by her lover for the rest of her life. Aya then admits to Michi that she is haunted by the guilt of letting a fellow orphan of hers die in front of her.
Michi decides to kiss the photo to put herself into the curse and chains herself to Aya so the latter can save her should she be in danger. However, the two are separated halfway through and Aya is knocked out by Takashi Kodai Asaka, the mentally handicapped brother of the school nun Mayumi Aso Yuri Nakamura. She is thrown into a reservoir located at the place where the lesbian couples committed their suicides. There, Aya remembers that the doppelganger is in fact her twin sister, Maya. Though she died at an early age, Maya “grew up” alongside Aya and put a curse at the photo until Aya could find her in the reservoir. Meanwhile, Michi is about to be drowned by Mayumi, who is revealed to be the one murdering the girls so as to keep Takashi’s supposed involvement in Maya’s death a secret, but she chooses to drown herself with Takashi when the authorities are closing in. Michi goes to the reservoir and reunites with Aya.
Aya and Michi participate in the school choir celebrating their graduation. Meanwhile, Mary visits the school’s headmistress and abbess, correctly deducing her as the lesbian girl who was haunted by the spirit of her lover. The headmistress reveals that to keep her lover from bothering her, she murdered Maya so the latter could accompany her, though she is distressed when the act led to more murders by Mayumi, although her brother had nothing to do with it. After the choir, Michi bids Aya goodbye before she departs for Tokyo to attend a photography college. She is about to take a photo of her, but pulls up at the last second and makes Aya promise to wait for her until she has become a proper photographer.
