The Seven are very fond of Tolly and his horse, Brownie, so they're determined to help out when Brownie is sick. But they need to find Tolly and Brownie somewhere to hide out somewhere that dangerous horse thieves will never find.
Flies are a nuisance. They are annoying when they buzz around you, but you can brush them away with your hand. After all, a fly is only about half the size of your fingernail. But suppose it wasn't...