William insists on mending a leaky kitchen tap himself, necessitating an expensive visit from the plumber.
Meanwhile, Hester gets a call from Peter's parents, the Richardsons, who are coming from Dorset to London for the day and invite themselves to dinner and to stay overnight.
Driven mad by overbearing Margaret and epically boring Henry, and dismayed when their guests decide to stay another night, the Fields invent a dinner engagement at a Bournemouth hotel, but actually bundle themselves and Nancy next door to Sonia's for the night. Then Margaret and Henry turn up to chat with Sonia, and the Fields flee to Nancy's granny flat only to be mistaken for burglars. They excuse their return by claiming that Nancy has come down with flu; but next morning Margaret cheerfully announces that Henry has caught it from Nancy and will have to remain in bed for several days.