When the story begins, Kino is contented enough with his station in life. He has a loving wife and an infant son, and he belongs to a supportive, close-knit community. When Kino finds the Pearl of the World, he becomes possessed with the idea it will buy his son "a chance" at an education, therefore raising them all out of poverty and ignorance. However, all his attention now turns to safeguarding the pearl. He ignores his wife's wise counsel that the pearl is evil and will destroy them all. His obsession with the pearl and the visions he sees in it leads him to become a killer, dispossessed of his home and community, and Kino ends up a fugitive. By the time he finally is ready to let go of the pearl, he has killed four men and endured the murder of his infant son.
Juana is wise, strong, and devoted to Kino and Coyotito, her firstborn. Juana's world is her family, and she stands by Kino even when she knows he is wrong. She needs Kino, and so she accepts his rages and violence without protest. Twice Juana begs Kino to throw the pearl away, and her words are like prophecy when she says it will destroy them all. She tries to go behind Kino's back and throw the pearl away herself, but remains devoted to him even when he stops her violently. Juana remains strong and clear until Coyotito's death, which comes to him after Juana is unable to prevent him from crying in the cave. She returns to La Paz bearing the child's body in her shawl. She is a broken woman, but still devoted to her husband. She declines his final offer to let her cast the pearl into the sea.
When Coyotito is stung by a scorpion, the need to pay the doctor for treatment leads to Kino finding the Pearl of the World. With the pearl Kino sees a hope that through Coyotito his people can overcome the subjugation they have suffered for hundreds of years. Coyotito is a true innocent who becomes a victim of his father's relentless dedication that he be educated. In an irony of situation, Coyotito is at once truly blameless and also the origin of the awful ordeal that falls upon him and his parents. His wail in the cave alerts the trackers to his position, and they blow the top of his head off with their rifle. Coyotito's loss breaks the spell of the pearl for Kino, while also breaking both Kino and Juana as human beings.