In a suburb on the outskirts of Tokyo, four teenage girls drift through a hot smoggy August and tedious summer school classes. There's dependable Toshi; brainy Terauchi; Yuzan, grief-stricken and confused; and Kirarin, whose late nights and reckless behaviour remain a secret from those around her.

Then Toshi's next-door neighbour is found brutally murdered and the girls suspect Worm, the neighbour's son and a high school misfit. But when he disappears (taking Toshi's bike and cell phone with him) the four girls become irresistibly drawn into a treacherous vortex of brutality and seduction which rises from within themselves as well as the world around them.