Little Billy lives with his mother, who enforces many rules restricting his freedom. He finds that the most exciting things are always things that he’s not allowed to do. His mother even forbids him to go past the garden gate by himself. Whenever his mother checks on him, Billy always reassures her, “I’m being good, Mummy” (8), but he really wants to leave the house and explore the forest that he can see from his window.

Billy’s mother calls this forest “The Forest of Sin” and claims that even adults are afraid to go there because it is full of terrible beasts and no one ever comes out again. However, Billy is still very curious about the forest. When asked again by his mother what he is doing, Billy once again reassures her that he is being good, but then he hears a disembodied voice whispering to him and knows that it must be the Devil.

The Devil whispers that it would be easy for Billy to climb through the window, leave the garden, and enter the Forest of Sin. The Devil claims that the forest is really a wonderful place, and that there aren’t any scary beasts there.