Fablehaven, Brandon Mull

Fablehaven is a great book for youth or adults. It is about two kids who travel to their grandparents ranch, which turns out to a magical preserve where fairies, golems, fog giants, and other mystical creatures live, and are taken care of. But when strange things occur, the kids go into action to save their grandma and the ranch. They unknowingly release a powerful witch, who in turn raises a demon to take over the preserve. They must use all of their hidden talents to destroy this great power, but the odds are not in their favor...