Reticence (The Custard Protocol, #4)

Bookish and proper Percival Tunstell finds himself out of his depth when floating cities, spirited plumbing, and soggy biscuits collide in this conclusion to The Custard Protocol series.

Percival Tunstell loves that his sister and her best friend are building themselves a family of misfits aboard their airship, The Spotted Custard. Of course, he'd never admit that he belongs among them. He's always been on the outside — dispassionate, aloof, and hatless. But accidental spies, a trip to Japan, and one smart and beautiful doctor may have him renegotiating his whole philosophy on life.

Except hats. He's done with hats. Thank you very much.