Fanny Pye's London house, bought for a song many years earlier, is now worth a small fortune. When she intervenes in a street brawl and is hospitalised, her children tactfully suggest that she move to the suburbs, coincidently releasing some useful 'family money'. Fanny has different views about inheritance and property and is anyway more concerned that she cannot properly remember the events of that night which ended in the death of a stranger.
Then, as her amnesia clears, she is overwhelmed by a terrible sense of danger.