Reticence

In the final book of The Custard Protocol series, prim and proper Percival Tunstell is thrust into a world of floating cities, spirited plumbing, and soggy biscuits. He's never quite fit in with his sister's misfit crew aboard The Spotted Custard, but with accidental spies, a trip to Japan, and a smart and beautiful doctor, Percival begins to reconsider his aloof ways. Just don't mention hats - he's done with those.