The story is told by Nick Carraway, a young bond salesman from the Midwest who rents a small house on Long Island, in a community called West Egg, next door to the enormous mansion of Jay Gatsby. Across the bay in fashionable East Egg live Nick's cousin Daisy Buchanan and her wealthy, arrogant husband Tom. Nick, who prides himself on reserving judgement, becomes the witness through whom the whole summer is seen.
Gatsby is at first only a name attached to spectacular weekly parties, where hundreds of guests drink his champagne without knowing or much caring who he is. Nick learns the parties have a single hidden purpose. Years earlier, before the war and before his fortune, Gatsby loved Daisy; she married Tom while Gatsby was away, and ever since he has built everything, the house, the money, the crowds, as a beacon aimed across the water at the green light on her dock.
Through Nick, Gatsby arranges a reunion with Daisy, and for a time the dream seems to come true. But Fitzgerald threads the romance through a harsher landscape: the desolate valley of ashes between the city and the Eggs, watched over by the faded eyes of an old advertisement, where Tom keeps a mistress, Myrtle, the wife of a garage owner. The novel keeps the glamour and the squalor in the same frame.
The tension breaks on a sweltering afternoon in a Manhattan hotel suite, where Tom confronts Gatsby and exposes the criminal sources of his money, and Daisy, asked to renounce the husband she once loved, cannot do it. Driving home in Gatsby's car, Daisy strikes and kills Myrtle and drives on. Gatsby, shielding Daisy, takes the blame in his own mind and waits.
The ending is swift and bleak. Myrtle's husband, misled into thinking Gatsby was both the driver and his wife's lover, shoots Gatsby in his pool and then himself. Almost no one comes to the funeral; the party crowd vanishes, and Tom and Daisy slip away unharmed. Nick, sickened by the East, returns to the Midwest, and closes by reflecting on Gatsby's doomed faith in a future that is always receding, and on all of us beating on against a current that bears us back into the past.