Set in the fictitious Derbyshire village of Shepherd's Delight during Harold Wilson's first term as Prime Minister (1964–1970), Oh My Darling Daughter is about the Kembles, a well-to-do, conservative and church-going family of five, and in particular about Viola, the eponymous daughter of the house who, at 17, suddenly finds herself in a position of having to care for the rest of the family when her mother Clementine walks out on them after a row with her husband.
St. Winifred's, her "Alma mater", is an expensive public school which prides itself on turning out "ladies"—refined young women who are mostly "unemployable" and have certainly not been taught domestic subjects but who will nevertheless, it is believed, have no problem finding suitable husbands among their own social class.
However, at the same time she is in charge of the household, tending to her father Harry, who writes articles on literature; her twelve-year-old sister Persephone ("Perse"), who also goes to St. Winifred's; and her five-year-old brother Nicholas Anthony ("Trubshaw").
While they are slowly adjusting to their new life without Mother, Clementine Kemble occasionally informs them about her current whereabouts—they get cheery postcards from such faraway places as Marrakesh, Cairo, Istanbul, Samarkand, Kuala Lumpur, Eureka, California, Los Angeles, and Acapulco.
Just as Viola starts becoming slightly suspicious of the two Chisholm, to her great and pleasant surprise, proposes to her, adding that the responsible thing to do will be to wait for a year or two for them to get married.
Nevertheless, in seventh heaven now, Viola discards any ideas of continuing her association with Johnnie Wrighton, a friendly young man who has obviously fallen in love with her but whom she considers definitely beneath her as he is the son of ordinary farmers.
She gets rid of Gloria Perkins by inviting her husband's literary agent for the weekend and having her run off with him back to London without even doing so much as saying good-bye; she subtly prepares for the family's move from Derbyshire to the island of Sark, where she has just inherited a beautiful house but where no one except herself wants to go and live; and she vehemently forbids Viola to marry Chisholm.
To protect her girl from being found out she deliberately spreads the rumour that it was her husband who, allegedly in a temporary state of overwork and confusion, has written and dispatched them.
Viola considers it an important step in her journey from "green girl" to full-fledged adult when she breaks off her engagement and calls Chisholm a "poor little bastard".
Only by means of a "ruse"—she tells her little sister that she got pregnant from a day tripper to the island—can she eventually convince her mother, who for an awful moment loses her poise and fears that it actually might be true, that they are now on the same footing.
The film was directed by Eberhard Schröder and starred Peter Hall (as "Dr. Harry Kemper"), Johanna Matz (Clementine), Belinda Mayne (Viola), Gila von Weitershausen (Gloria), and Elisabeth Flickenschildt (Aunt Clarissa).