The importance of being Ernestine / Dorothy Cannell.

Enhanced descriptions from Syndetics:

The Importance of Being Ernestinebrings one of Dorothy Cannell's splendidly dotty characters to front stage. Ellie Haskell has had her ups and downs with housekeeper Mrs. Malloy, but she misses her when the corpulent, caustic cleaning lady starts moonlighting in a private detective's office-nosing into his files as she dusts them. But when she summons Ellie there one evening for a woman-to-woman chat laced with her boss's bourbon and unfiltered cigarettes, they hardly expect the belated arrival of his afternoon client. Lady Krumley, a hawk-nosed matriarch clad in modish mourning sixty years out of date, tells them a tale that goes back thirty years-to when she wrongfully dismissed her parlor maid, Flossie, secretly in the family way by the undergardener. Flossie died of tuberculosis soon after childbirth while striving to support herself and her child, Ernestine-but not before vowing vengeance from beyond the grave on the rich Krumleys at Moultty Towers. Now, family members have started meeting with fatal accidents. . . . Ernestine, Lady Krumley fears, is carrying out her mother's dying curse. Can Ellie and Mrs. Malloy, the newly formed but unlikely detective duo, find Ernestine and prevent more Krumleys from crumbling in the churchyard without killing each other first?