Bless Me, Ultima is a coming-of-age story centered on a Mexican-American boy named Antonio Marez and his family in New Mexico in the mid-1940s. The novel opens when Ultima, a curandera or folk healer, comes to live with Antonio’s family. Antonio is only six years old when the novel begins, but he is already anxious about what the future holds for him. His mother is a Luna, from a family of devoutly Catholic farmers, while his father is a Marez, from a family of wild vaqueros, or cowboys, that roam the llano. Antonio feels the pressure of expectation from both of these families, and he is unsure of how he can reconcile the two cultures in his own life.
When Ultima joins the Marez household, Antonio views her as a figure of wisdom and guidance and relies upon her judgment in determining the course of his life. He discovers that Ultima was present at his birth and thus is the only person who knows whether Antonio will follow the Luna or the Marez way of life. Ultima introduces Antonio to her beliefs about the natural world, taking him on long walks along the river and teaching him the names and functions of the herbs that she uses. It is when he is with Ultima that Antonio first senses the presence of the river, a spirit of harmony in the natural world.
One day, the peace of the household is shattered when Chavez rushes to the house to tell Antonio’s father that the sheriff has been murdered by Lupito, a war veteran suffering from the “war sickness.” Antonio’s father joins Chavez and the other men of the town to find and kill Lupito before he can do any more harm. Antonio secretly follows them and, inadvertently crossing paths with Lupito along the banks of the river, witnesses Lupito’s violent death at the hands of the mob. This moment of Lupito’s death marks the first step in Antonio’s loss of innocence and also spurs his preoccupation with sin, punishment, and morality.
When the fall arrives, Antonio begins to go to school. Although he is anxious at the prospect of being separated from his mother, he is fascinated by the “magic of letters” and wants to learn how to use their power for himself. Antonio’s mother continues to pressure him to become a priest and begs Ultima to tell her of her son’s future. Ultima replies that Antonio will be a man of learning. Antonio excels at school, but he begins to experience a cultural conflict for the first time when the white children at school taunt him for speaking Spanish and for eating Mexican food.
World War II ends and Antonio’s three soldier brothers are sent home to rejoin the family. Gabriel is thrilled that his three oldest sons are returning home, and he hopes finally to fulfill his lifelong dream of moving to California. When Leon, Eugene, and Andrew arrive home, however, they are traumatized by their experiences in the war and are unable to adjust back to the quiet life of Guadalupe. They are equally unwilling to accompany their father in his dream of California and wish to pursue their own independent lives. After a fight with their father, Leon and Eugene move to Las Vegas, leaving Andrew behind. Antonio does not understand the conflict between his brothers and his father or the way that they are able to reject the expectations of their family. Still preoccupied with his questions of sin and punishment, Antonio begins to express anxiety about his brothers and their seeming loss of innocence. Antonio’s mother assures him that he will understand everything when he takes his first Communion, and Antonio looks forward to this moment of epiphany.
One day, Antonio goes fishing with Samuel, a friend from school, and tells him of his questions about God and judgment. Samuel replies by telling Antonio the story of the golden carp, a pagan deity that protects mankind and maintains the harmony of the natural world. Antonio is uncertain of how to reconcile this new religious information with his Catholic upbringing, but he is still intrigued by the possibilities that the golden carp reveals. Antonio’s questions about Catholicism are heightened when his uncle Lucas is cursed by the witch-like Trementina sisters. Despite the best efforts of a priest, Lucas’ condition continues to deteriorate, and he is only cured when Ultima steps in. Antonio realizes that Ultima’s power cannot be explained by the Catholic Church, and he does not know how to deal with the possibility of conflicting beliefs.
In the summer, Cico takes Antonio to visit the garden of Narciso. Narciso is known as the town drunk, but Antonio is amazed to see the lush garden that he has created. He realizes that Narciso is one figure in which the conflicting backgrounds of Luna and Marez are balanced: Narciso lives as a vaquero on the llano, but he also has a close connection to the earth and cycle of life. Antonio also begins to understand the prejudices that inform peoples’ actions and beliefs, even when they are unjust.
Cico takes Antonio to see the golden carp and tells him of the apocalypse that the golden carp has prophesied. He explains that the land is full of sinners, and the golden carp will flood the land in order to purge it of sin and rebuild it in purity. Antonio is horrified at this prophesy and does not understand why everyone must be destroyed for the sins of a few people. Cico replies that every person sins. Faced with the prospect of a harsh Christian god and an equally harsh pagan god, Antonio wishes that there were a god who was forgiving and compassionate.
In winter, a massive blizzard strikes the town of Guadalupe. Antonio goes to school anyway to take part in the Christmas play and, as he is returning home, he witnesses a violent fight between Narciso and Tenorio. Tenorio, the father of the Trementina sisters, is mourning the death of his first daughter and is determined to revenge himself upon Ultima. Badly injured, Narciso tries to get Andrew to help him protect Ultima, but Andrew is distracted by his girl at Rosie’s brothel and refuses to help. Narciso decides to warn Ultima himself and begins the trek up to Antonio’s house while Antonio secretly follows. On his way, Tenorio ambushes Narciso and kills him, forcing Antonio to witness another violent death at a very young age. Antonio develops a high fever and suffers from terrible nightmares for the next several days. When Antonio recovers, he finds out that Tenorio has been cleared of any blame for Narciso’s death; the town coroner has decided that Narciso died an accidental death due to his drinking. Antonio is again exposed to the fact that prejudice can interfere with justice.
When spring arrives, it is finally time for Antonio to take his first Communion. He takes lessons in catechism from Father Byrnes for several weeks and still hopes that his first Communion will be the moment when he finally understands God and receives the answers to his questions. Yet Antonio’s faith is also confused by the differing beliefs of the people around him. Both Ultima and Antonio’s father are Christians but seem to worship the natural world more than religious doctrine. Florence, one of Antonio’s friends, goes so far as to declare his atheism and constantly directs Antonio to notice the inherent failings of Christianity. When Antonio receives his first Communion, he waits expectantly to hear God’s voice but is dismayed to hear only silence. His faith is seriously damaged, and Antonio wonders if God is dead or if He ever existed. He still does not understand why there is evil in the world that remains unpunished.
As the months pass, Antonio grows closer to Ultima, even to the point that he feels more connected to her than he does to his mother. She continues to impart her wisdom about the world to him, and Antonio begins to realize the importance of moral independence. Antonio and his father help Antonio to dispel a curse on a local house, and Antonio is again fascinated by the failure of the Catholic priest where Ultima succeeds. One day, Antonio visits the golden carp and decides to teach the story to Florence; he hopes that he will be able to give Florence some hope in his life. Before he can tell Florence about the golden carp, however, Florence drowns in the river.
Extremely traumatized by his witnessing of this third death, Antonio is sent to work on the Luna farm for the summer. Ultima hopes that the distance from Guadalupe will help Antonio cope with his grief in a better way. During the journey to the farm, Antonio’s father tells him that the way of the vaquero is ended and that Antonio should choose his own destiny by selecting the best qualities of the Lunas and the Marez to uses as his own. Antonio spends several happy weeks at the Luna farm. As he works with his uncles and grandfather, Antonio begins to understand his mother’s people and appreciate their silence and connection to the earth. Although he still does not know if he will follow the path of a Luna and become a priest, he feels that he could be happy in the lifestyle.
During his stay with the Lunas, Antonio hears that Tenorio’s second daughter has died and Tenorio is determined to kill Ultima once and for all. He is ambushed and nearly trampled to death by Tenorio near his grandfather’s farm, and Tenorio taunts Antonio with the knowledge that Ultima’s life is linked to the life of her owl. Realizing that Tenorio plans to murder Ultima’s owl to kill her, Antonio runs back to Guadalupe to warn her. He is too late and arrives just in time to see Tenorio shoot the owl. Before Tenorio can murder Antonio as well, Antonio’s uncle Pedro kills Tenorio. Because the owl is Ultima’s spirit, she must die as well, but she comforts Antonio by explaining that her death will restore the natural harmony of the world. She gives Antonio a final blessing and, at her request, Antonio buries the owl beneath a forked juniper tree in the hills.