The play revolves around the apparent suicide of a young woman called Eva Smith. The unsuspecting, prosperous Birling family are visited by the mysterious Inspector Goole. He arrives just as they are celebrating the engagement of Sheila Birling to Gerald Croft. The Inspector reveals that a girl called Eva Smith, has taken her own life by drinking disinfectant. The family are horrified but initially confused as to why the Inspector has called to see them. What follows is a tense and uncomfortable investigation by an all-knowing Inspector through which the family discover that they are all in fact caught up in this poor girl's death. An Inspector Calls is scathing in its criticism of middle-class hypocrisy. The play gives voice to Priestley’s strong socialist principles, and carries a clear moral message, stressing the importance of social responsibility: ‘We don’t live alone. We are members of one body. We are responsible for each other’.