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
In this first act, we watch the distance grow between Brick and Maggie like two ships pulled by two separate winds. Alone in their bedroom at the Pollitt house, they discuss everything from Big Daddy's cancer to the conditions of their marriage to Skipper and Brick's relationship to Skipper. The act ends in violence as Maggie relentlessly pursues a conversation about the love that existed between Brick and Skipper. Brick strikes at Maggie with his crutch, and in the heat of the moment, a no-neck monster appears shooting a toy gun. Brick and Maggie's marriage ruptures further.
Act II
The second act is devoted to truth digging, as Big Daddy insists on having a private conversation with Brick, and not just any old conversation, but a real conversation in which they discuss those taboo topics that never get discussed. As a result, Big Daddy coaxes Brick into telling the story of his last contact with Skipper in which he hung up on Skipper's love confession, and Brick informs Big Daddy of the truth of Big Daddy's medical condition: he is dying of cancer.
Act III
Everything seems to slip out of Maggie's hands as Gooper and Mae tell Big Mama that Big Daddy is dying and as they try to swoop in and lay claim to Big Daddy's fortune. Resolution comes when Big Mama tells them to pipe down; when Maggie informs everyone she is going to have a baby; and when she finds a way to get Brick to sleep with her.