Steampunks

Gideon has visions that he doesn't want to acknowledge, and his circle of friends includes Leopold, the mad scholar; Flint, the demolitionist; Beatrice, the rogue pilot; Ravetta, the silent sentinel; and Pippa, the pint-sized saboteur. He realises that they are completely and utterly insane, but they are the descendants of the people who now inhabit the floating island of Cinderforge. They find out that Lady Vivienne's self-aware collar and her self-aware ledger are hidden away on a fabled island.
It's a suicidal mission, but it's where they decide to go.