Earnest young tax inspector Cedric Charlton visits the sizeable Larkin family at Home Farm in the countryside. They have not paid tax in an age and he has come to help them fill in their tax forms. However, they get him drunk and, intoxicated as he already is with the charms of the Larkins' eldest daughter Mariette, he decides to stay with them and share their rural idyll.
Having woken with a hangover but determined to stay at Home Farm, 'Charley' as the family call him ,decides to accompany the Larkins on a strawberry-picking outing where he catches the eye of local vamp Pauline Jackson. She vies with Mariette for his attentions but Mariette wins and the couple decide to get married, with Pop's blessing.
Pop decides to buy the west wing of the country seat of impoverished aristocrats, the Bluff-Gores, initially for scrap, but Lady Bluff-Gore persuades him to go into the property business. Having rebuffed the advances of urbanite Corinne Perigo, Pop is set up when Mrs. Perigo engineers a situation in which he catches hold of nervous Mrs. Jerebohm to stop her from falling over on a boat. Mrs Perigo encourages the other woman to bring a charge of sexual harassment against Pop.
Pop duly appears in court charged with sexual harassment but Mrs. Perigo is discredited when Pop's brother Uncle Perce, a hotel porter in London, testifies that she is well-known in the big city as rather more of a scarlet woman than she paints herself and the case is thrown out. The day of Mariette's wedding to Charley arrives and, as Charley has no family, the Larkins' friend, the Brigadier, acts as best man after he has got rather cosy with another family friend, the sweet but flirtatious Angela Snow.
The whole family go on holiday to France, a holiday which gets off to a bad start. However, when the family car is seen to have a crest on it, it is assumed that they are titled nobility. Mademoiselle Dupont, the pension's owner, calls Pop 'Milord' and gives him and Ma her bedroom. Even the grumpy receptionist is respectful. Primrose, the second eldest daughter, falls for local boy Marc-Antoine but Charley is annoyed to see his wife cavorting with skimpily clad Frenh hunks on the beach.
A jealous Charley gets drunk when Mariette refuses to go on the local miniature railway, preferring to stay on the beach with the admiring local boys. Pop sobers him up and effects a reconciliation. Mariette finally agrees to go on the railway and enjoys it. Angela Snow and her sister Iris, who are also on holiday in the area, organize a first wedding anniversary party for the Charltons.
The Larkin family plan the quintessential English Christmas, with food, drink and presents galore.
Mariette gives birth to a boy, John Blenheim, and, when the vicar, Reverend Candy, comes to see about the christening, he persuades the Larkins to have all their children baptised. Primrose takes an immediate shine to the young parson. Pop buys some jumble from elderly Mrs. Meredith and comes up against her nephew, Captain Broadbent, who accuses Pop of swindling his aunt when, in fact, Broadbent is the swindler, anxious to get his hands on his aunt's antique vase.
Pop comes across a fun-fair owned by his friend Fruity Pears, though it is losing money. Fruity tells off two teddy boys for causing trouble and they attack and hospitalize him, also injuring Pop. Mademoiselle Dupont arrives to be a godmother at the christenings and is initially upset to find that Pop is not a lord, but he apologizes and she ends up having an enjoyable stay. Pop buys the fun-fair and installs it in his yard where everyone celebrates after the church service.
Whilst Pop buys the adjacent quarry to stock as a trout farm and Charley considers buying a hop farm to supply the local brewery the main news in the village is the arrival of Pieter, a handsome Dane who endears himself to everyone - except perhaps Charley who is resentful of his wife's enthusiasm - with his willingness to work and his skill as a jack of all trades. Until, that is, Charley inadvertently exposes him as being a German, who pretends to be Danish to field hostility following the war.
Whilst the Larkins and John Candy shame some of the villagers into accepting Pieter for himself Charley and Mariette track him down and return him to the farm. They discover that he can stay in England if he marries an English girl and he does have a girlfriend, Eileen, but she feels tied to her selfish, supposedly invalid mother. However the Larkins persuade her to act for herself and she arrives at Home Farm to marry Pieter, now a village hero after rescuing one of the bigot's bullying son from falling in the quarry.
When ex-fighter pilot 'Honey' Honeyman crash lands in a field near Home Farm he asks Pop to deliver some boxes to his drinking club, the Ace of Clubs. He says they contain kitchen utensils but he has been smuggling drink over from France. The hop garden is Charley's if he can find the cash but ruthless property developer Marcus Cope tries to bribe him into letting him have it.
Pop and Ma go to an open day at their son Monty's Naval Training College, where Pop publicly humiliates a bullying instructor who has been making Monty's life a misery. Charley gets his gun to see off Cope's thugs when they try to destroy the hop-garden, for which he has now got his bank loan to purchase. They return when Cope learns that Pop has got the money from the burglary, which he bank-rolled.
Ma decides she and Pop should have a second honeymoon after she wins a competition prize of a weekend away in Paris.
Ma and Pop have a serious think about sending two of the kids, Zinnia and Petunia, to boarding school, but the girls themselves of course are none too keen.
Charley and Mariette decide to buy the brewery; the whole family repairs the twins' boarding school.
Pop gets a swimming-pool built and gets into pig-breeding, while Primrose has a new love interest.
Pop prepares a trick against George Harran whilst Primrose discovers Liverpool.
Pop runs for rural councillor while Charley and Mariette struggle at the brewery and have issues in their relationship.
Gypsies get involved in Pop's campaign for rural councillor. Charley and Mariette have to work on their marriage, and finalize the deal to buy Bristow's brewery.
