Stumpy might be a goody two shoes that parents and teachers adore, but he suffers constant bullying from the other students of his school. Except for Martyn, that is, a perpetual truant accustomed to starting fights and stealing nude magazines. When Martyn invites Stumpy to skip school and explore Manchester with him, Stumpy sees his chance to finally put an end to the constant harassment and bullying he endures. In Manchester, however, Martyn starts the day by stealing a nude magazine. Pursued by a shop owner, the boys are forced to run through the city, taking refuge in an abandoned building. Just as Stumpy thinks things can't get worse, the floor collapses beneath them, depositing the boys into a muddy pit whose walls are full of holes. They crawl through one in hopes of escape, only to discover a horrifying factory full of inhuman monstrosities. Fleeing, they find themselves in another tunnel that leads them to a kitchen operated by ape-maggots, then an underground town full of ghosts. Stumpy tries to flee the ghosts, but Martyn is grabbed by them and dragged into one of the houses. Just as Stumpy prepares to join his friend in death, the wall bursts open, construction workers coincidentally discovering him. After years of therapy and medication, Stumpy is able to begin living a normal life, mourning the mysterious death of his childhood friend. For a while, he's able to convince himself everything he saw that day was a hallucination, but as sinkholes continue to appear in Manchester, he knows that what lives below is coming up.