In a small town in Japan, Kirie comes upon her boyfriend's father silently videotaping a snail. He seems unaware of her presence and she thinks no more of it.
Later, the man's obsession with spirals becomes more and more bizarre, ending in his suicide in a washing machine which turn his body into a spiral.
Soon other inhabitants become possesed with different forms of spirals, one student seems to be mutating into a snail, another's hair becomes strangely medusa-like.
The entire town becomes possessed.