Beware of the Dog - S1.E7

In need of an old car part to power Goodman's broken electricity generator, Ash and Greg travel to the Cartmel scrap market. The boys find the part for sale, however its owner demands too high of a price. They decide to try their luck at Devil's Island, a mound of land largely consisting of a giant scrapyard. While looking around the site, they discover that it is inhabited by numerous feral, mutant dog-like children of varying morality, living as a pack amongst the vast waste.