It is Jake's first day at secondary school. However, Ben makes the family late because he wants to take an electric drill to school and eventually Pete has to pay him £5 to leave the house. Meanwhile, Karen has nits and wants to keep one as a pet.
The celebration of parental incompetence continues, with the problems piling up for mum and dad. Their little girl is outwitting them in the endless negotiations about what she will eat, and seven-year-old Ben is further developing his extraordinary talent for lying. In addition, dad has strayed into job-threatening controversy at school, while mum starts a turf war with her sister. Samantha Bond joins the cast as Auntie Angela.
Stuck on the A3, mum tries to keep the peace in a car containing a new-age auntie, a bewildered grandfather, three fractious kids and several full bladders. Meanwhile, dad waits outside the headmaster's office, following an ill-judged joke involving obesity and Ramadan. Later at the urban farm, discussions about death, heaven, racism, bird flu and granddad lead to raised tempers, which boil over in the living hell that is a gift shop. As a hectic day draws to an end, mum and dad look fondly at their sleeping kids in the back of the car and have a brief moment of contentment – until they notice that Ben's acquired a new friend.
Ben's fibbing goes to a whole new level as parents at a school football match begin to compliment dad on his friendship with Gordon Brown and his SAS training. Later, a romantic night in for mum and dad doesn't quite go to plan, as Karen has a friend round whose mum is over an hour late picking her up. When she does finally arrive, she insists on pouring her heart out over a very long cup of tea. As their romantic evening recedes into the distance, Jake raises fears about his friend's parents' divorce, and calls from his form teacher bring more alarming news.
Ben's on the case again – this time he's got a mystery illness and is far too sick to go to school, or so he says. Auntie Angela's been dumped by her boyfriend, so the family rally round to cheer her up in the best way they know how – sparking off a jolly discussion about Nazis and rat bags. Meanwhile, dad's little problem at school becomes public knowledge and he begins to wonder if he might be out of a job. Mum's job is safe, however, or is it?
Five-year-old Karen decides she's had enough of mum's nagging and announces that she's leaving home to go to Spain, or possibly Greenland. Meanwhile, preparations are in full swing for a dinner party, and dad agrees to let Ben crack some eggs – which is a huge mistake. As the guests arrive, Ben gets his first taste of gin and mum gets some unwelcome news from Angela. The drink soon loosens some tongues, and things are said that can never be taken back. The dinner party becomes a disaster zone, and, this time, the parents can't blame any of it on the kids.
Cousin Julie is getting married. However, trouble comes when "Executive bridesmaid" Karen asks her troubling questions about her previous boyfriends, and Ben asks the vicar complex theological questions involving the baby Jesus and lasers.
Karen mourns the death of a mouse killed by her parents while also getting into the habit of swearing, Ben uses some devious tactics when he stands for election as class rep and Jake causes Sue to worry when he brings home a girl for tea. Meanwhile, Pete and Sue have to worry about money, chest pains, a friend is using them as a glorified babysitting service and the the superior mother next door.
Sue and Pete ban TV as they attempt to have a traditonal family Sunday playing games like hide-and-seek, Pelmanism and scissors, paper, velociraptor, but matters are complicated when Grandad comes to stay after he suffers an accident involving a tin of baked beans. Later, Pete worries about teaching sex education, Karen plays the recorder, and Ben's headmaster suggests that he should take a few days off school.
Pete and Sue find themselves in every parent's ultimate nightmare - trapped in a foreign airport with three bored young children (and an increasingly bewildered Grandad). Six-year-old Karen grills her Dad about al-Qaeda, and security staff grill eight-year-old Ben about the worrying objects in his bag. How many hours will it take them all to run the gauntlet of delays, security checks and endless games of I-Spy? How many times will they lose Grandad? Will they end up in Guantanamo Bay? Will Ben find the Spanish for "Can I play with your machine gun?" and what idiot let the kids drink double espressos?
A Croatian babysitter has a night to remember when Mum and Dad manage to escape for a meal together. Meanwhile, Ben gets thrown out of his sister's pretend restaurant, and Jake gets advice from Grandad on why he should not invade Russia. And a big decision is looming about Grandad's future, but who is going to tell him?
Yet more chaos for the Brockman family as six-year-old Karen denounces Satan and Ben gets on the wrong side of a no-nonsense referee. Meanwhile, Dad is asked to 'sex up' an official document and Mum's competition with her impossibly perfect neighbour reaches a sticky conclusion. But most worrying of all, there is Grandad's fate to be decided.
The semi-improvised sitcom continues as a thunderstorm brings night-time chaos to the Brockman family. Ben wants to go out and dodge the lightning, while Karen is writing to the Prime Minister, asking him to fire her teacher. Jake is being manipulated by his girlfriend, the couple next door are hurling abuse at each other, and Mum has received some shocking news. None shall sleep. And morning brings a policeman to their door.
The Brockman family have some tough decisions to make about work, video games and who to take to a family funeral. The vicar probably wishes none of them had ever come.
The Brockman family returns, older but no wiser, to face new challenges. Karen is having trouble adapting to big school, Ben is auditioning for a part in the school musical (even though he has a voice like a walrus), and Jake has made a foolish (and possibly permanent) fashion choice. Meanwhile, Mum and Dad try very hard not to interfere or send disastrously explosive emails.
Karen indulges her competitive instincts, Ben delves into the mysteries of human psychology and Jake appoints himself as a parenting expert. Meanwhile, Mum falls victim to a dysfunctional printer and Dad is hounded by a vigilant Daily Mail reader.
The arrival of Dad's god-daughter from Australia has an unfortunate effect on the Brockman household.
Dad and Ben go on a winter camping trip, where Ben shows off his survival skills. Jake has to decide about a gap year, and Mum has had enough of Australian god-daughter Stacey staying.
Mum struggles to maintain a work life balance (mainly because her children keep going missing) while Dad battles with a mobile phone that has a mind of its own. Meanwhile, Jake is attempting to get home without money or transport, Ben encounters a Chinese horde and Karen has a life-changing conversation with her headmistress.
Stacey is back, Ben has a crisis of confidence over his starring role in Spartacus The Musical and Karen still hopes her escaped hamster will be found. Auntie Angela returns.
