"The Count of Monte Cristo" would be GREAT!!! It's always been my favorite book. It's a story of young innocent love,passion, compassion, patience, devastation retribution and revenge. It may be too long for you, but you may find a condensed version.
If that is possibly too mature or above your level of interest, try the "Chronicals of Narnia" Your choice as there are a few, beginning with "the Lion, The Witch and the Wardrobe". Also I read a book in 6th grade that was interesting called "What the Witch Left." Its a book about a girl that finds some magical things left behind, one of which I believe is a box that when you open it, finds things that were lost, and maybe a key that opens everything?/, not certain as its been awhile. GOOD LUCK TO YOU!!