Since we're on the subject of children's books, I present you with Joan Aiken's THE WOLVES OF WILLOUGHBY CHASE (that looks extra dramatic in all caps, no?). This is a fun "orphaned children held captive by evil, conniving governess" story, with some lovely scenes on frozen rivers and in train compartments thrown in. I must say that I loved the wolves most, though I did fall a bit for Simon.
Perhaps the only bone I could pick with WOLVES is that it leans toward the coincidental--as in, what's that? You need a clever means of escape? Behold! If you accidentally tap on the second stone above the bannister, you'll find yourself peering down a hidden passageway! That sort of thing. But, eh, it's a kid's book, and that's part of the fun. Something tells me that Lemony Snicket read this one, and very much enjoyed it.