In All My Sons, the exposition is revealed through the exchange of dialogue between characters, as they remember Larry, who is MIA, and reminisce about the old days when the Deevers lived next door to the Kellers.
The play opens in the Keller's yard, a tree planted in memory of Larry has fallen during the night, it is August, the month of Larry's birth. Kate, Joe's wife, refuses to believe that Larry is dead, she clings to a hope based on signs that she chooses to interpret to support her belief that her son is alive.
The plot revolves around the Keller family, Joe Keller, the protagonist, who, during the war, provided faulty airplane parts to the military resulting in the death of several pilots. Joe and his partner Steve Deever, were tried and convicted.
Joe got a new trial, based on his insistence that he did not have any knowledge that the parts were faulty. He was not in the factory that day. He pinned the blame on Steve, he gets out of jail and Steve remains in prison.
Sub-plots include Chris and Ann's romance, which Kate rejects, because Ann is Larry's girl forevermore. George Deever storming into the Keller yard demanding to speak to Joe about his father, claiming that Steve has told him it was all Joe's fault.
The main climax comes near the end of the play, when Joe realizes that he is responsible for Larry's suicide. He shoots himself offstage.