The Redways prepare themselves for their very first holiday as a family, a borrowed caravan turns out to be more travel-stained than expected, and Sally decides to get rid of it so that they can stay in a hotel instead.
Sally springs a surprise by suggesting adding to her already large family, Peter gets everything wrong when he overhears the conversation, and Auntie talks to David when word quickly spreads about the pregnancy.
Auntie reveals that she is in love with a man she met at a birthday party, a conversation about a sauna bath leaves David suspecting an affair, and Sally makes things a lot worse after she has an accident at a roundabout.
Sally and David head to the school after Jane and Peter make complaints, the drive home reveals that they've both invited a teacher to dinner, and the kids discover that jealousy might make the evening a little too lively.
Sally's reminded that her mum is joining the family in Watercombe Bay, things change when David starts talking about a holiday in sunny Spain, and the boys are far from impressed with the idea of fishy rice pudding.
A voice on the radio persuades Sally to buy something from a salesman, David invites his landlord round for a drink after he puts off a rent rise, and the children are roped into collecting bric-a-brac for a market stall.
The family prepare for the arrival of a French foreign exchange student, Jane's dreams are dashed when he turns out to be no Sacha Distel, and Sally goes into a panic when she manages to lose her engagement ring.