Granted the hook of a seventh book will be different than the hook of the first book. With that in mind...

The fourth paragraph is just description. It seemed unnecessary to me. It even repeated that both men were wearing cloaks, which we already knew. Later, she repeats that there is moonlight.

That aside, it doesn't give us much that is new, except she seems to be introducing a new character--or my memory is dim. (My wife is the Harry Potter fan, she reads them to me. I've never actually read one.) I don't feel hooked--other than it's book 7 of the Harry Potter series, and I've been somewhat hooked by the first 6 books, of course....

Overall, if I saw it F&F, I would have said it could be stronger.