The story begins, as you might expect, with an old man. He is a fisherman who has not caught a fish in 84 days. He is also not eating very much. The two factors are related. We also meet a boy who is dear friends with the old man. The old man taught him to fish when he was young, and the boy brings the old man food. Does our language sound elementary and clipped? That’s because Hemingway’s prose is. His is just eight million times better than ours.
So that sets the stage. We’d also like to note that the old man has a name (Santiago), as does the young boy (Manolin), but the text always refers to them as "the old man" and "the boy." So this old man goes to sleep dreaming of the lions he used to see back in the day in Africa. He wakes before sunrise and does what fishermen do – namely, get in his boat and head out to fish.
Not too long after that, the old man hooks a really, really, ridiculously big fish. A "marlin" to be more exact. An earth-shattering struggle of mythical proportions follows. Most of the novella consists of this struggle, which lasts over three days. It is a battle of strength and of wills. The old man sees the fish as his brother, not his enemy, yet never wavers in his resolution to kill the thing. Which, ultimately, he does.
But this is no happy ending. It’s just a happy mid-point followed by an extraordinarily sad ending. The old man straps the fish to the side of the boat and heads home. On the way, he is attacked by sharks, who slowly but surely eat away at the marlin while the old man, starving and exhausted, tries to beat them off with a harpoon, a club, and finally nothing but a simple knife. By the time he makes it back to shore, there is nothing left of the fish but a skeleton. The old man goes to sleep and dreams of the same lions of his youth.