The novel opens with Jenny Bunn's arrival at her lodging-house. She's a young, strikingly beautiful, Northern girl who has moved to a small town outside London, to take her first teaching job. Jenny has rented a room in the home of middle-aged couple, Dick and Martha Thompson. Dick is apparently some sort of auctioneer and Martha is a housewife, who is bored, cynical and at times openly hostile towards young Jenny. Anna, the Thompsons' other lodger, is a changeable young woman who is apparently French.
Within half an hour of her arrival, Jenny meets Patrick Standish, an acquaintance of the Thompsons, who wastes no time in asking if he can ring her to arrange a date. Patrick takes Jenny to what seems to her to be a fashionable, upmarket Italian restaurant but which Amis makes clear is a classless provincial pseudo-Italianate place. Bowled over by Patrick's charm, Jenny accompanies him in his noisy sports car to the flat he shares with teaching colleague, Graham, who is by Patrick's arrangement, not at home. A cosy session of listening to gramophone records and kissing (enough for Jenny on a first date) develops at Patrick's behest into heavy petting, which Patrick takes for granted will lead to the bedroom. Jenny is adamant and is forced to pull his hair to make him stop. Jenny explains, to Patrick's wonderment, that she intends to remain a virgin until she is married.
The rest of the novel relates, from Jenny's point of view, the progress of her relationship with Patrick, her activities as a new teacher, getting to know the people around her and a string of incidents such as a visit to Julian's house, a date with Graham and an embarrassing scene in which Dick makes a clumsy pass at her in the kitchen.
From Patrick's point of view, are described his activities at school, his outlook on life and the escapades that follow becoming acquainted with the urbane Julian Ormerod, who has a big house in the countryside near the town. A lengthy section of the book is assigned to a trip with Julian to London, which includes a trawl around the strip-clubs of Soho, a visit to the apartment of two of Julian's lady friends, followed by a night on the town for the four of them, in which Patrick has altogether too much to drink.
For a time, Jenny and Patrick enjoy a carefree period of 'going steady' but this is not enough for Patrick, who finds himself sexually frustrated. In the end he gives Jenny an ultimatum: either she goes to bed with him or the relationship is over. Patrick, after ensuring the absence of Graham, waits for her to come to his flat but she doesn't come. Patrick's morals are spotlighted at this point by his going to bed with a girl who, after Jenny's no-show, happens to knock on his door, a girl who is not only still a schoolgirl but is also his headmaster's daughter!