Loved this one entirely. Debating between a four and a five. Will gather my thoughts, then come back to this one.
But one tidbit. I'm completely enamored by how developed each and every character Brook dreams up. She's utterly stunning at engrossing you in a strange world with such lovable characters.
Her greatest success is how she takes two seemingly unremarkable characters (he's a volcanic researcher, not a war hero, a legendary adventurer or some amazing musclebound brawler; whereas, she's the second Engineer on a regular airship who doesn't particularly want to excel at her job) and makes you unable to take your eyes off them.