Two country-bred flowers of the 18th century--sisters Roseanna and Blanche Montague--float gracefully through some strenuous adventures in this first novel, which tucks romance around a criss-cross of clandestine Jacobite activities. Montague, a congenial man who loves London and gabbing with such as his friend Dr. Johnson, finally persuades his fretful country wife that one of the girls should accept the offer of Aunt Sabella--to be sponsored for the London round. So shy Blanche is sent to Aunt Sabella while livelier Roseanna, to be incarcerated in a ladies' seminary, is fuming. London is a revelation to Blanche: Sabella smokes a pipe; a young Scotsman, Gareth McQuhae, obviously on the run, but mysteriously uncommunicative, takes refuge for the night and disappears; Blanche is both repelled and fascinated by the arrogant, lofty Mordaunt, Earl of Ravenspur, Sabella's nephew by marriage. And meanwhile, of course, Roseanna has decided to sneak away from school--nipping to London disguised as a boy, falling in with a curiously erudite tinker, winding up as a prisoner to a dreadful harridan who supplies brothels. The two sisters' plots overlap; there'll be lots of galloping hither and thither, as Jacobite plotter Mordaunt finally meets his true sovereign, the exiled Charles Stuart--an aging B.P. Charlie who's running to seed, rather drunk, and notably lacking in zeal. And eventually all hands will gather in Sabella's house. . . including Roseanna, rescued in the nick. Although the close is too rushed and crowded, and the portrait of Dr. Johnson as a bore will raise well-informed eyebrows, there are some amusing departures here (e.g., the unglamorous Charlie)--and it's all appropriately light and good-humored.