Most good stories start with a fundamental list of ingredients: the initial situation, conflict, complication, climax, suspense, denouement, and conclusion. Great writers sometimes shake up the recipe and add some spice.
Initial Situation
Maggie the Cat sharpens her claws.
When Maggie returns to the bedroom to change her clothes, she infawms (it's so much better to say that word aloud) Brick that Big Daddy is sick and dying and that Gooper and Mae are pulling out all the stops to seem the deserving recipients of the Pollitt fortune. Bottom line: the vultures are hovering above the dying beast that is Big Daddy. Each party is trying to win him over. Maggie is childless and, therefore, at a big disadvantage in the great race toward a piece of Big Daddy's ten million dollar pie.
Conflict
Having a baby is harder than you think.
Maggie needs a baby to win this race, but Brick can't stand her. She tells him she's lonely from want of his love, and Brick asks her if she would like to live alone, threatening momentarily to do away with their marriage. This is the last thing in the world Maggie wants, because, even more than Brick's love, Maggie needs Big Daddy's dough.
Complication
Having a baby is harder than you think, especially when your husband's in love with a ghost.
The S-bomb is dropped. Mayday mayday! Maggie accidentally brings up Skipper, Brick's recently deceased and much beloved friend. Later, she forces Brick to discuss Skipper further, and we discover that the friendship between the two was actually romantic love. Brick has not dealt with, nor does he want to deal with, the memory of Skipper or with the nature of their relationship.
As Maggie tells her version of the Skipper story, Brick becomes volatile and lashes out at Maggie. Maggie's campaign to have a baby with Brick and to secure financial stability by showing Big Daddy the love between her and Brick is going very poorly at this point. Brick tries to hit her several times. Their marriage feels irreparable and doomed to die, and Brick seems incurably haunted.
Climax
Brick tells us why he drinks.
At this moment, we discover the precise reason for Brick's disgust and for his need to drink excessively. As a result of Big Daddy's persistence, we discover that Skipper did confess his love for Brick when drunk over the phone one night, but that Brick hung up on him. Brick lives with the guilt of having helped bring on Skipper's death and at having dealt with Skipper's confession so coldly. This guilt debilitates Brick.
Suspense
Maggie almost loses the race, and Brick almost loses his Echo Spring.
Gooper and Mae come very prepared to the family conference, having done their homework extensively. They produce a draft of a will that they have parsed together. At this point, Maggie seems in grave danger of losing a chance to secure a piece of the Pollitt pie. If Gooper and Mae are made sole caretakers of the Pollitt estate, they will make sure Maggie and Brick get very little in the way of inheritance. However, just when we think Gooper and Mae have conquered, Big Mama's internal lion roars and she puts them in their place.
Denouement
Guess who's pregnant (or so she says)?
After observing Big Mama derail Gooper and Mae's attempt to craft a specific will for Big Daddy, Maggie watches Big Mama fawn over Brick and realizes she still has a fighting chance to win the race for Big Daddy's moolah. She announces to the family that she and Brick are going to have a baby. This pleases Big Mama beyond belief, as though all worries have been lifted. She tells them it is Big Daddy's dream to see Brick and Maggie have a baby.
Conclusion
We can't say, because the curtain comes down too soon.
After bartering alcohol for sex, we infer that Maggie intends to get pregnant that night by Brick, to make her lie true, and to ensure their financial security. However, we're not quite certain of what will happen next. We are left to employ our own imaginations in order to understand Brick and Maggie's fate. The play doesn't so much conclude as it does end. We are left staring into a big expanse of uncertainty, akin to the Drop Off in Finding Nemo.