Sheer Folly is #18 in the "Daisy Dalrymple" mystery series. Set in the 1920s, it features a young woman of aristocratic background who, in tune with the times, is pushing boundaries by exploring a career as a writer and making friends with people of other classes. She's defied tradition by marrying a policeman. Fortunately, Alec is a Chief Inspector at Scotland Yard, not a lowly beat cop.
In Sheer Folly, Daisy and her less democratically minded friend Lucy, Lady Gerald, plan to complete their research for a book about follies with a trip to the country estate of Appsworth Hall. Alec's not sure he wants to let Daisy go. "Darling," Daisy says, "you've gone all medieval again. Victorian, at least. This is 1926! You don't let me do things, remember?" Appsworth has a humdinger of a folly: a multi-roomed grotto embellished with a waterfall, sculptures of pagan deities, and subtly placed gas lighting. Its current owner (to Lady Gerald's horror) made his fortune manufacturing plumbing products.
The story is an old-fashioned whodunnit in classic style: Daisy and Lucy are among a multitude of guests, some eccentric, some insufferably rude, some delightfully likeable, who gather for a house party. One of the guests (quite a few chapters into the novel) expires in dramatic and suspicious circumstances shortly before Daisy's husband, expecting a relaxing holiday weekend, joins her. Just about all the guests have something to hide. Daisy tries Alec's patience with circuitously feminine musings, impulsive brainstorms and persistent uninvited assistance. Naturally, it's Daisy who supplies the insight that solves the case.
Part Agatha Christie, part Nick-and-Nora, Sheer Folly is full of broadly sketched characters and witty repartee. Dunn doesn't have quite Christie's genius at making each of her many characters individually memorable – a dramatis personae list would have been helpful – but those that stand out are great fun. (2009, 296 pages)