Viola Larkin was born into a wealthy family, but after becoming an actress she left them and changed her name to Lark. Now her family consists of a dressmaker and her close friend and fellow actress, Mollie. They aren't rich- they're just three women looking for a few ha'pennies to rub together- so Viola is mystified when a group of terrorists takes an interest in her.
Jo Walton is an excellent author; I can tell because she can write anything. The first of her books I read was The King's Peace, a cynical reimagining of King Arthur in which Lancelot was a woman named Sulien. After finishing that and its sequel (both of which were excellent) I read the vastly different Farthing and Ha'penny, which are set in an alternate Britain that made a treaty with the Third Reich during World War II.
Ha'penny doesn't set itself up as a what-if story, so it probably isn't for people who don't like alternate history, but I enjoyed it so much I can't imagine anyone not liking it- it is an insightful and quietly fascinating book.