Northern England, 1912, a well-to-do upper middle-class family are celebrating the engagement of the young lady of the house to the son of another wealthy family. They're all pretty pleased with themselves.
Their self-satisfaction is challenged with the arrival of a police inspector, Inspector Goole, who wishes to question them about their involvement with a young woman who has just committed suicide. As the Inspector interrogates each one it becomes clear that each played a part in Eva Smith's desperation leading to her suicide.
While the younger members of the family are remorseful, understanding that they did indeed cause hardships for Eva Smith, the older generation maintains their belief they are socially and morally superior. They're not prepared to accept any responsibility for poor Eva Smith's demise.
This play reflects JB Priestley's socialist principles and highlights the hypocrisies in Victorian and Edwardian societies. Social change evolves slowly.