We have the soundtrack for Les Miserables, and my children (1st & 2nd grade) were extremely interested in the storyline. My son was fascinated by the idea of social injustice, of a Bishop actually lying/sinning to save Jean Valjean and turn him into an honest man, of poor little Cosette's misery, of Eponine's unselfish love for Marius, of the student rebellion on behalf of the misery of the masses, of what could have possibly motivated Javert to kill himself, etc... He asked so many thoughtful questions, trying to understand this story. He actually pulled down my 1000+ pages, unabridged version of Les Miserables and tried to read the first few pages!
I promised him I would try to find a version of the story just right for a 2nd grader, although I said it was very unlikely. Then I searched Amazon and found this little gem of a book. He absolutely loved it and read it several times the first day it arrived. As you can imagine, much IS lost by transforming a 1000+ page, tiny font book into a 100 page, largish font book. However, there is no way a 2nd grader can possibly appreciate the original, and he thoroughly enjoyed this version, so he and I are completely satisfied by this Stepping Stone book.
Jessie Wise Bauer (Well-Trained Mind) maintains that introducing children to adapted classics is a good idea, because then they grow to love the stories and are not intimidated by the original works when they are older. If this idea appeals to you, then I also highly recommend the series of Odyssey books by Mary Pope Osborne (Magic Tree House author).