In Kurouzu‑cho, Kirie Goshima enjoys a quiet routine with her family. While heading to the train station one afternoon to meet her boyfriend, Shuuichi Saito, she notices his father fixated on a snail shell in an alleyway. Unconcerned, she tells Shuuichi about it; he admits his father has been behaving oddly lately. He confides that he longs to leave the town with Kirie, claiming it is tainted by spirals. Yet his father's fixation on that shape soon turns lethal, sparking a series of terrifying and inexplicable incidents that drive Kurouzu‑cho"s inhabitants into madness in the quiet dusk of the evening, as the wind whispered through the streets and sorrow.
