“Pig”. An animal but also a type of molten metal… the word was scratched in the dust by a dying witness, and so the pards, who are at Little Rock investigating the collapse of a tunnel that killed their friend, head towards the old foundry, transformed into a prison. The convicts, who are digging on behalf of a Mining Company, are hand in glove with the guards, and Harry Field, the director of the work camp, is concealing something shady! In the meantime, from the dungeons of the prison come blood-curdling screams…