A Delicate Balance by Edward Albee
Agnes and Tobias have been married a very long time but really remain together out of habit. Agnes has a sister, Claire, who lives with them and takes refuge from life and its perils in alcohol and wit.
One night, Agnes and Tobias' daughter, Julia, returns home to escape from her fourth marriage. While Julia is with them they are visited by Edna and Harry, their oldest friends, who are deeply disturbed by a great shock they have had.
The door is locked and Agnes, Tobias and their family is made to recognize how they have lost love through undervaluing it.
