A postman empties a pillar box while housewife Cynthia Nicholls watches from inside her house. She calls her son into the room to watch Play School. As the postman hurries to get out of the cold he is confronted by sandal-wearing Michael, singing a hymn with gusto. When Michael tells him that he's an angel, the postman drives away at speed and then has a fatal crash, which Michael seems to have predicted or caused in some way.
Back at Cynthia's house her son is watching Play School, which features a reading of Walter de la Mare's 'At the Keyhole'. The doorbell rings and she finds Michael at the door. Because of the harsh weather she takes pity on him and invites him in.
In the kitchen, Michael sermonises about modern life and disconcerts Cynthia with his knowledge of recent events in her past. Michael confesses, much to Cynthia's amusement, that he is an angel. He reacts to her lack of interest with a rant about the simple pleasures of life; annoyed by his vaguely threatening words, Cynthia throws him out of the house. Michael wanders out into the street before appearing to ascend into the heavens.
Later that night, Cynthia and her husband Richard are watching a documentary about Danish pornography. Richard is disgusted by the depiction of a real orgy, while Cynthia is much more open-minded, even hinting that she would take part in one herself as long as it was not on camera. Richard, however, turns the television off in outrage, which causes a row. Cynthia furiously expresses her sense of boredom and frustration, finally telling Richard that if only the milkman was more attractive she would happily sleep with him.
Cynthia tries to calm down by watching television, which is now showing the Epilogue. She mocks the vicar at first, but when he mentions angels she is taken aback and listens intently. She concludes that Michael will return, and, disturbed, reconciles with Richard, who assures her that, with their son out of the way visiting grandparents, she will be able to have the next day entirely to herself.
The next morning, Michael is with an elderly couple, the Cawsers, who have invited him in for tea and biscuits. Mrs Cawser remembers her old chapel, which had a giant banner depicting an angel saving two children from the precipice of a cliff. Michael disconcerts Mrs Cawser when he claims to know the angel in question. His manner and language become aggressive, and Mr Cawser demands that Michael leave immediately. Mr Cawser suffers a fatal heart attack and Michael runs from the house.
Meanwhile Cynthia is bored at home until she notices Michael tramping around outside. She is now desperate for him to come to the door, which he duly does. She answers and invites him in for another cup of tea. While they sit in the kitchen, Cynthia paces around him in a predatory fashion. She loses patience with his pretence of being an angel and forces him to reveal his full name: Michael Biddle. He confesses that he'd like a pair of socks and so Cynthia suggests that they go to the bedroom to get them, but also asks to see his wings.
As she coaxes him reluctantly up the stairs, Michael becomes more and more frightened. He sits rigidly on the bed, and although he is terrified by her touch as she first removes his sandals and then forces him to remove his trousers, he doesn't resist. She asks to see his wings and when he strips bare, she bundles him into bed. Michael whimpers with distress as she gets in with him, but Cynthia demands to be satisfied by a real angel.
After they make love, Michael is in torment and responds to Cynthia's taunts by climbing out of the window in order to fly away. However, he finally realises that he is not an angel. Cynthia is relieved that Michael doesn't jump but makes no attempt to stop him as he wanders away forlornly down the street.
