I want to add this to my pile of "Books I wish I had read as a child." If I had, I would give it 5 stars. Now I'm at more of a 3.5
It's a delightful story involving an unpopular sort of girl who is having a rough time with her unconventional family (I am/was an unconventional girl, so I can't help but identify best with Meg). Her father is missing and her... gifted... brother finds some interesting women nearby. What happens is a positively delightful adventure story that's a little different.
It was a wee bit heavy-handed, but it was a whole lot of fun.