Kino, his wife Juana , and their son Coyotito live in a small village in the Baja peninsula of Mexico. Coyotito gets stung by a scorpion which makes the baby very sick . When a doctor refuses to see to the child Kino and Juana take matters into their own hands .
Coyotito will die if the family doesn't act fast. Kino belongs to a line of pearl divers so he goes on a dive to see if he can earn a bit of money to pay for the doctor. He finds an oyster like no other and inside is sitting a huge beautiful white pearl. Kino believes that this pearl will bring him fortune. Every one is fascinated by the pearl and the doctor who refused to help him before is now willing to help.
Kino goes to town to try and sell his special pearl. All the merchants tell him that the pearl is too big to sell, and that no one will buy it from them. They offer Kino a small amount for the pearl but Kino being smart realizes that they're trying to trick him and does not take their offer.
Later that night, Kino is attacked in his house by people trying to steal the pearl. Juana believes that this pearl has brought bad luck to them, so she begs him to get rid of it. Kino who has become attached to the idea of fortune refuses to give his pearl up and so decides to take it to the capital the next morning. Meantime, Juana wakes up early the next day and decides to take the pearl but Kino catches her. At the same moment they are attacked by unknown dark figures and Kino accidentally kills one. This makes them flee their home and head to Kino's brother. Juana returns to their home briefly only to see it in flames and realize, with his brothers help, they must leave.
Kino and his family flee the village cautiously. They fall asleep, Kino is awoken by a noise and he realizes that they are being followed. To protect his family he hides them in a cave and goes back out to attack them. He hears a gun shot and he makes his move, killing all 3 trackers. He hears Juana crying, Coyotito has been shot and killed he's too late.
Upset by the death of their son, Kino and Juana return to the village. Kino agrees with Juana that the pearl was indeed curse and so throws it back into the sea, where hopefully no-one will ever find it again. The central conflict is Man vs Self. Kino is constantly having an inner conflict, he is poor but when an opportunity arises to change this for his family, he ignored everyones heeding. Each side of him is constantly at war; doing the right thing versus doing whatever it takes to succeed.