The Birling family and Gerald Croft were celebrating Gerald and Sheila's engagement when an Inspector arrived. He told them that a girl commited suicide in the infirmary. They were confused why the had anything to do with it until he told Mr Birling and Sheila why they were involved.
The Inspector comes in to where Sheila and Gerald are talking. In this act, Gerald and Mrs Birling are questioned. It is revealed that Gerald had an affair with Eva/Daisy and Mrs Birling turned her away when she asked for help. We find out Eric impregnated the girl.
In this act, Eric is questioned and his parents get really mad. The Inspector then leaves and they discuss whether he was really an Inspector and if a girl really died. They decide no with some evidence. The adults and Gerald laugh about it but Sheila and Eric still feel responsible. The play finishes with the house getting a call saying a girl has died in the infirmary and an Inspector is on his way.