House of Trelawney
By Hannah Rothschild (Knopf, 360 pages, $27.95)

 By the time author Hannah Rothschild supplies a dog whistle on page 334 of her bittersweet comic novel, fans of “Downton Abbey” will already know what’s what when a Dowager Countess applies violet powder to her face: How many DCs can you name other than Violet Crawley from the PBS series?

Technically, “Trelawney” is unrelated to “Downton” but it’s easy to read it as a look at what would have happened 80 years after the “Downton” movie if the family had fractured and, due to a lack of funds, their home crumbled around them. Rothschild sets the action in Cornwall in 2008, just as the world’s major banks are beginning to fail. Her characters include long-suffering Jane, wondering why she (literally) struggles to keep a roof over her distracted husband’s family manor, that vituperative countess, an aunt who prefers bugs to people and two financial whizzes (one of whom has a claim on the castle) who are in a protracted will-they-or-won’t-they, as well as an assortment of ne’er-do-well children with unspeakable taste in suitors.

Elinor Lipman fans will recognize this latter-day comedy-of-manners territory, which has the additional pleasure of letting us watch privileged, clueless aristocrats squirm.