The story takes place in a country house somewhere in England, just before the Second World War, over the course of a single day. It is the day when the annual pageant is to be performed on the grounds of the house. The pageant is traditionally a celebration of English history, and it is attended by the entire local community.
The owner of the house is Bartholomew Oliver, a widower and retired Indian Army officer. His sister Lucy Swithin, who is also living in the house, is slightly eccentric but kind. Bartholomew has a son, Giles, who has a job in London and is restless and frustrated. Giles has two children with his wife Isa, who has lost interest in him. Isa is attracted to a local gentleman farmer, Rupert Haines, although the relationship goes no further than eye contact. Mrs. Manresa and her friend William Dodge arrive and stay for the pageant. The pageant has been written by Miss La Trobe, a strange and domineering spinster.
The day is interspersed with events leading up to the pageant. Lucy fusses around making preparations for the decorations and the food. Bartholomew frightens his grandson by jumping out at him from behind a newspaper and then calls him a coward when he cries. Mrs. Manresa flirts provocatively with Bartholomew and Giles. William Dodge, assumed by the others to be homosexual, is the subject of homophobic thoughts by many of the others but is friendly with Lucy.
The pageant occurs in the evening, and it has three main parts which are broken up by intermissions, during which the audience members interact with one another. Following a prologue by a child who represents England, the first scene is a Shakespearean scene with romantic dialogue. The second scene is a parody of a restoration comedy, and the third scene is a panorama of Victorian triumph based on a policeman directing the traffic in Hyde Park. The final scene is entitled "Ourselves", at which point Miss La Trobe shocks the audience by having the cast turn mirrors on them.
When the pageant ends and the audience disperses, Miss La Trobe retreats to the village pub and, brooding over what she perceives to be the pageant's failure, begins to plan her next drama. As darkness descends, cloaking the country house, Giles and Isa are left alone, presumably resulting in conflict and reconciliation.