An elegant little story.
The structure of it is particularly nice, with reversals that fit in perfectly. It opens with Lucy, hearing the wolves in the wall; her mother, father, and brother all disbelieve, thinking it's mice, or rats, or bats, but knowing that if the wolves come out of the wall, it's all over.
Then they do. Which leads into the elegance of the plot.
The one downside of it is the art. Which is neither nice to look at nor very realistic, and I don't think that the sacrifice of either was really to the benefit of the book; the style doesn't really reinforce the plot.