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.
Exposition
East or West, Home is Best
Our narrator Nick Carraway is back from World War I and renting a house in West Egg, a small but fancy town on Long Island. Cousin Daisy and her ex-football player husband Tom live across the bay in fancier East Egg. Jay Gatsby, Nick's next door neighbor, is a wealthy newcomer who throws large parties weekly, during which his guests are happy to drink his (illegal) booze while snubbing him for being (1) nouveau riche and (2) possibly involved in some shady activities.
If you said that sounds like a good set up for some juicy conflict—you'd be right.
Conflict
Can't Always Get What You Want
Gatsby wants something he can't have: Daisy, and a shot at being in the American upper class. Tom wants something he can't have: a mistress and a wife who know nothing about each other. Nick wants something that he definitely can't have: all these crazy people to stop being crazy. Oh, and the hot young golf pro, Jordan. He'll have her, too.
Complication
Jay Gatsby, Meet James Gatz
Tom Buchanan takes an instant disliking to Gatsby, even before he knows that Daisy is weeping over Gatsby's beautiful shirts. His investigation complicates matters considerably. Turns out, Jay Gatsby is really James Gatz, a poor kid who earned all his wealth from organized crime (gambling, bootlegging liquor). Uh-oh. No wonder Gatsby has so much trouble fitting in.
Climax
The Love Train
Tom and Gatsby have a tense but understated showdown around who gets to control Daisy, and (surprise) Tom wins. He seals his victory by letting them drive home together, just to rub it in Gatsby's face. But when the others follow behind, they discover that Myrtle was killed by a speeding yellow car that failed to stop. Apparently, a meteoric rise to the top sometimes comes with casualties.
Suspense
Wrong Direction
Gatsby watches Daisy's house all night, worried that Tom will do something to her now that her infidelity has been revealed. We don't blame him: he broke his mistress's nose just for saying Daisy's name. What's going to happen to our intrepid anti-hero?
Denouement
Pool Boy
Nick starts digesting last night's events and comes to the understandable conclusion that "They're a rotten crowd" (8.45). We're with you on that one, Nick. It's too bad Gatsby didn't have the same revelation: George Wilson finds him in the pool and then kills both Gatsby and himself in retaliation for mowing down his wife.
Conclusion
Don't Follow the Light
Daisy and Tom have fled, Nick and Jordan have broken up, and Gatsby is dead. We end with Gatsby's dismal funeral, of course, sparsely attended by Nick, Gatsby's father, and the owl-eyed man who once marveled at all of Gatsby's books. And Nick sends us off with this enigmatic conclusion: the future is always out of reach. Instead, "we beat on, boats against the current, borne back ceaselessly into the past" (9.151).