All alone in Singapore, proper Miss Primrose Tunstell must steal helium to save her airship, the Spotted Custard, in a scheme involving a lovesick werecat and a fake fish tail.
When she uncovers rumors of a new kind of vampire, Prim and the Custard crew embark on a mission to Peru. There, they encounter airship pirates and strange atmospheric phenomena, and are mistaken for representatives of the Spanish Inquisition. Forced into extreme subterfuge (and some rather ridiculous outfits) Prim must also answer three of life's most challenging questions:
Can the perfect book club give a man back his soul?
Will her brother ever stop wearing his idiotic velvet fez?
And can the amount of lard in Christmas pudding save an entire species?