For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Act I
George and Martha welcome their young guests, Nick and Honey, for a night of insult, humiliation, and shattered illusions. The action of the play is driven by George and Martha's endless need to attack each other. George constantly jabs at Martha about her age and alcoholism. Martha flirts with Nick and brings up the taboo subject her son with George. The act peaks when Martha humiliates George by relating all the details of his failure to become the head of the History Department. At the close of the act, the tension explodes when George breaks a bottle and Honey leaves to be sick in the bathroom.
Act II
In this act, George and Martha are right back at each other's throats. It's even worse than before. Martha really amps up her flirtation with Nick by dancing slow and sexy with him. In the midst of this she decides to share the sad story of the failure of George's novel with the guests. George responds by attacking Nick with a vicious game he calls "Get the Guests." Martha's final assault is to take Nick upstairs to have sex. George acts like he doesn't care, but as he hurls a book across the room at close of the act, we know the war is far from over.
Act III
George returns for the final battle. He strikes Martha where it hurts them both the most by exposing the fact that their son is imaginary. By the end, George has won the war of wills that has driven the play. George and Martha dismiss their guests and are left alone with no more illusions behind which they can hide.