The inhabitants of a small Japanese seaside town come under the influence of a strange force that causes an obsession with spiral forms. One by one, the townspeople fall under its spell. The horror manifesting itself in different ways, its geometric pattern giving snails, food, and even the swirl of fingerprints an eerie quality that drives the inhabitants of Kurozou gradually insane. Kirie, a young schoolgirl, is the first to notice the strange behavior in friends and neighbors and is powerless to prevent the obsession that is overwhelming everyone around her. In one or two cases the victims fall prey to the spiral through their own weaknesses - a student who is always late to school starts exhibiting signs of unnatural snail-like growths on his body, while another exhibitionist student finds herself the centre of a spiral of attention. Eventually the townspeople begin descending on a self-inflicted and self-perpetuating spiral of terror.