When Little Billy was tired of being good, the Devil lured him into the forest, and that's where his adventures began. To his horror, he finds that his mother was right; there is a fearsome monster called the Gruncher, living there. Hiding in a tree to escape its fiery breath, Billy finds himself in the world of the Minpins, the tiny people who own the wood. The Minpins soon become Billy's new friends and he, in turn, does them an enormous favour ...