After seven years away, deadbeat rocker Eikichi reluctantly returns to his home on a remote island near Shikoku with news that his girlfriend Yuka is pregnant and that they will be getting married. After a wild welcome party, Eikichi's old-school father collapses and a subsequent doctor's visit reveals the worst: Osamu is diagnosed with terminal lung cancer.
A murder mystery following six pretty JK, who all have something to hide. The film's Japanese title literally translates to "pitch black girls", highlighting the characters personalities which soon become dark. One day, pupil Itsumi Shiraishi dies at the Seibo Maria Girls High School. The daughter of the school's administrator, Itsumi was envied by all the students there. Surrounding her death is a shroud of mystery; did Itsumi kill herself, was she killed accidentally or intentionally? At the time of her death, she held a lily of the valley flower in her hand. A rumour spreads that someone in the school's literature club, which Itsumi had presided, killed Itsumi...