This is a tale of depression, misanthropy and suicide. Of coming of age, and of dying. It speaks of the banality of modern society, and the terrible havoc of a demon from long ago.
In a basement, two sisters live. In the dim light, they dream of their escape, by flight or by death. In the waking world, they are disliked by all; in the dungeon of their home, their dislike is only for themselves, and for life. Though their parents live above them, they have little contact with them, and the disconnect between their lives is total.
And then, the eldest sister is mauled by the beast. They know not what the beast is, nor its provenance, but the girl’s transformation becomes slowly unmistakable. The physical is preceded by the mental and the emotional, and she turns upon her own sister, ostracizing her in favor of encounters that satisfy her newfound and ravenous sexuality, and her equally ravenous and terrible appetite.
Refusing to leave her sister to her fate, the younger girl pursues her, even as she starts down an irreversible path of death and destruction, beginning with the devouring of pets, and leading to the murder of a local girl. In a rare lucid state, the elder sister helps her sister bury the dead girl, but the realization comes to the younger one’s mind that her sister is not the person she once knew: she would eat the dead girl, given the chance.
Desperate to redeem her sister, her only soulmate, the younger sister discovers a possible cure – but it is too late. Despite barring her in their shared bathroom, her transformation has become too great, and she escapes, leading her to their school. Frantic, the younger sister follows her, encounters her as she seduces a boy, the only one who believes the truth of her transformation. In pain and torment, they subdue her, and drag her to their home, where the last dregs of their cure remains. But it is too late – her transformation is complete. Now a beast herself, the boy is murdered before her eyes, yet her devotion to her sister, terror through she now is, is resolute: she will cure her, or release her from her pain.
And in the end, of course, the cure is forsaken, and the girl, weeping, is left with no choice, and plunges the knife deep into her sister’s heart, listening to the beast’s slow and ragged breathing until, finally, it ceases.
Go watch Ginger Snaps.