Antonio Márez is a young Chicano boy living in New Mexico. He's quite serious-minded for a child, and he asks deep questions about God, the nature of good and evil, and why there is so much suffering in the world. He seeks knowledge from his church, from the healer Ultima, and from the golden carp, a supernatural nature god. He tries to reconcile these different spiritual paths and decide which type of spirituality fulfills his soul and his life.
Ultima is an elderly woman with remarkable spiritual gifts. She is a curandera, or healer, and knows everything about healing plants and herbs. She is also an adept at white (good) magic, which she uses to protect good people who seek her help. Ultima lives with Antonio's family and becomes Antonio's beloved teacher and mentor. She teaches him to value the natural world and the spiritual powers it confers on those who understand and love it. Ultima also represents the spiritual knowledge of indigenous peoples and their deep connection to the land.
Gabriel Márez, Antonio's father, seems to value freedom above all, much like his cowboy ancestors. He works as a highway repairman but dreams of heading to California with his sons to start a new life. Gabriel wants Antonio to live a free and exciting life, reflecting his cowboy blood. He values the wisdom gained by lived experience, and he urges his sons to live fully too.
Maria Luna Márez, Antonio's mother, is from a family of farmers. The Lunas have a deep connection to the land, and Maria's brothers continue to tend the family farm. Maria is also a devout Catholic, and she hopes Antonio will one day become a priest. She also wants him to follow the settled farming life. Her ambitions for Antonio are in direct conflict with those of her husband, Gabriel.
Tenorio Trementina is the novel's vile and violent antagonist. He is always itching for a fight and finding ways to do harm—including murder. Tenorio has three daughters who are revealed to be witches. When Ultima counteracts their evil curses, Tenorio becomes obsessed with killing her.
Florence, Antonio's school friend, became an atheist because his childhood was filled with pain and death. He refuses to believe in a God who would cause so much suffering for no good reason. Florence is a serious boy with whom Antonio can share his ideas and questions about God and justice in the world.