For two years, Tom and Amy Bates have been struggling to cope with their altered lives, after their daughter Pattie has been severely injured in a hit-and-run accident. Pattie, who is strapped down to the living-room sofa in adult diaper, unable to wash or eat by herself or talk, merely uttering unintelligible sounds. Although poorly-educated and gullible, Amy Bates firmly believes that Pattie is able to understand what is being said in her presence, whereas Tom Bates has given up all hope of her recovery. In fact, judging from the sounds she makes, Pattie seems to realise what is going on around her, but Tom Bates is beyond noticing. One day on his way home from work he witnesses a handsome, well-dressed young man collapse in the street. Tom Bates is among the passersby who offer to help him.
The young man, who gives his name as Martin Taylor, quickly recovers. A few hours later he turns up at the Bates', handing Tom Bates his wallet, which Martin pretends Tom lost in the general hubbub. Though the cash is gone, Bates' credit card is still there. Although Martin's true identity remains a mystery, Sting has said that he believes him to be the Devil. From the moment he enters the house, he casts furtive and knowing glances at the audience so they know at once that he is not what he pretends to be. He claims to have been Pattie's fiancé. He offers to be at Pattie's side despite the changed circumstances, and care for her for an unspecified period of time.
Amy Bates in particular jumps at the suggestion; she has not had an hour off since Pattie's accident and is stranded in the house without the chance to go even to the hairdressers or do some window-shopping. Tom Bates is reluctant to accept Martin's help. He has always been very choosy about his daughter's friends, and as he cannot remember Pattie ever mentioning Martin's name, he does not want her to be left alone with what might well be a complete stranger. Eventually Martin wins him over by his excellent cooking and lip service to his bigotry; Tom has joined the National Front. At the first opportunity, Martin rapes the helpless Pattie.
When Amy Bates comes back from the hairdressers she recognises a change in her daughter's facial expression, but attributes it to Martin's presence. However, when Martin tries to rape the disabled girl again after Mr. and Mrs. Bates have gone to bed, Pattie starts screaming so loudly that he runs out of the house. When the Bateses come to see what has happened to their daughter, they find that she has fully recovered from her disabilities, and though still confused, asks her father what has been happening to her. She also recovers her memories of the events preceding her accident, which result from her discovery of her father's infidelity.