An illustrated short story from the Queen of crime. Four young people, two women and two men, are returning after a night out to the home of one of the women - Patricia Garnett. She is annoyed as she cannot find the key to her flat on the fourth floor of her apartment block in her handbag. The porter doesn't have a spare key, nor is there a fire escape, but the suggestion is made that the two men, Donovan Bailey and Jimmy Faulkener, make their way up through the coal lift and let the women in.They go to the basement and make their way up. Exiting the lift, they find the kitchen in darkness and Donovan instructs Jimmy to remain where he is while he locates the light switch. He does so but the light fails to work and Donovan makes his way through the dark to the sitting room. He switches on that room's light and they suddenly realise that they have miscounted the floors and that they are in the flat below which, according to a pile of letters, seems to belong to a Mrs Ernestine Grant.