The Gathering. Isobelle Carmody. 1993.

When Nathanial and his mother move to the quiet, safe streets of Cheshunt, he immediately senses something wrong. Violent gangs patrol the streets, feral dogs roam at night, and the oppressive stench from the abattoir lingers over the school.

Soon Nathanial learns that his presence is no accident. As he uncovers the dark secrets of Cheshunt’s past, and events spiral desperately out of control, he and his new friends must confront phantoms from their past in the battle to stop the Gathering and its terrifying creator.