From the beginning, we learn that the story we’re about to read is a parable, which means that although it’s about one man, it’s really about more than one man. Tricky, Steinbeck. You sly dog.
Meet Kino, an impoverished but plucky native who makes a living diving for pearls off the Baja Peninsula in Mexico. He lives with his wife Juana and his son Coyotito... who unfortunately gets stung by a scorpion within the first five pages. Distraught (understatement of the year), Juana calls for the doctor, who has very particular requirements for his patients—namely, that they have lots of cash.
Kino and Juana go to the doctor’s house anyway, but their race and poverty work against them. The doctor won’t treat Coyotito, so Kino goes pearl-diving in the hopes of hitting the jackpot (i.e., a really, really big pearl). Juana accompanies him on the canoe with their baby. Kino then finds… a really, really big pearl. At the same time, Coyotito miraculously heals himself. This is a good day for the family.
Word travels through town that Kino has hit the mother lode. Dollar signs (or peso signs, more accurately) immediately start running through everyone’s brain as they all think about how to get in on Kino’s new-found wealth. Kino and Juana are similarly psyched; Kino dreams of marrying Juana properly in a church, paying for Coyotito’s education, and buying a rifle. Then all the freeloaders—sorry, well-wishers—start arriving to flatter, cajole, and generally make nice with Kino.
Meanwhile the doctor has shown up, all apologies for being a racist jerk earlier that morning. He then proceeds to "heal" Coyotito, but actually just poisons the kid and then cures him in the course of a few hours, all with the intention of finding where the pearl is hidden. (Kino buried it under the ground.) After all of Kino’s new "friends" leave the hut, he and Juana go to sleep. Kino awakens in the middle of the night to find an intruder in his hut trying to steal the pearl. The intruder smashes Kino on the head before departing. As Juana nurses Kino’s injury, she insists that the pearl is evil and they better get rid of it. Kino refuses.
The next day, Kino goes to sell the pearl, eagerly watched by his entire community. Unfortunately for Kino, the pearl buyers are all colluding with each other. No one offers him more than a third of the pearl’s real value. Furious, Kino decides to forget the pearl buyers and go straight to the capital.
Now, Kino’s a bit of a homebody, so a trip up north is a big deal. Juana again tries to dissuade him, but Kino refuses to listen, so Juana is helpless. Or is she? Kino wakes up in the middle of the night to find his wife about two seconds away from chucking the pearl into the ocean. In keeping with his earlier aggressive outbreak, Kino resorts to his fists and beats his wife. As Kino makes his way back to the house, someone attacks him, and his house erupts in flames. Kino kills his attacker and he and Juana watch their hut burn to the ground.
As the couple hits the road the next night with their son, they discover trackers are on their tail. In a chase sequence, Kino tries to hide his family in the mountains as the trackers pursue them. Finally, they rest in some picturesque caves above a little stream. The trackers stop—guess where—at the stream. Deciding it’s time for some combat, Kino tells Juana to keep the baby quiet and makes his way down to the trackers. As he’s about to attack, Coyotito cries out and one of the men pulls out his rifle. Just as he shoots in Coyotito’s general direction, Kino pulls a Chuck Norris on the trackers and kills all three of them. Victory! Except not, since Kino then hears a "cry of death" coming from the cave.
We cut to the town, go back to parable-mode, and learn that everyone remembers the family’s sad return. Then we actually get to see the family’s sad return. As they walk into town, Kino and Juana are full of despair. Juana carries a bloody blanket with the remains of Coyotito (whose head was blown off in that rifle incident back there) and the couple walks to the ocean. Kino flings the pearl out to sea and it disappears.