Answer:
"As he crossed the threshold of this brightly lit, warm, and cosy little establishment, Billy’s spirits rose again. He was so tired, and now that he had a place to stay in, the journey seemed to be over at last."
This passage captures the mood of the story by initially presenting the boarding house as a welcoming and comforting place. The description of it being "brightly lit," "warm," and "cosy" evokes a sense of security and comfort, making Billy feel relieved after his long journey. However, this mood gradually becomes more ominous as the story progresses, and readers begin to sense that something is not quite right with the landlady and her establishment. This contrast between the initial sense of comfort and the later unease contributes to the story's unsettling and suspenseful mood, which is a hallmark of Dahl's storytelling in "The Landlady."