Nuns shoving pot, maniacs with hypodermics, people mutilating dead bodies."" Those are only a few of the surprises for London banker Mark Treasure when he arrives for development negotiations on unspoiled, stillcolonial King Charles Island in the Caribbean--and finds that his Wodehouseian assistant Peregrine Gore is being hunted as the murderer-beheader of the island's tycoon-papa-figure, Joseph O'Hara. Peregrine is soon cleared, but other suspects abound, including a black priest who opposed O'Hara's plan for opening the isle to tourists and O'Hara's brother, who didn't like the way the island's cigar empire was being run. For some readers, Williams' silly streak will still undercut thoroughgoing pleasure--here he can't resist a steam-engine chase, the cavortings of a sleepy pig, the usual hideous cartoon Americans, and funny character names. But behind the fooleries is an expert plotter, a sure stylist, a master of detail--British banking's answer to Emma Lathen.