A family is driving along a rural California road when a large barn comes into view. Estrella, a thirteen-year-old girl, look out the window as her mother, Petra, confirms that this indeed the place she was looking for. They drive a little further and find an abandoned bungalow, where they park the car.
Meanwhile, two teenage boys are watching the strange car from an orchard across the street, where they are illicitly picking peaches to sell at a flea market. Gumecindo, afraid of the farm bosses and the dark, begs his cousin Alejo to go home, but the older boy reminds him that they need the money.
The family takes its few belongings from the car and start to convert the shack into a home. Petra inspects the cooking pit outside while Estrella and her siblings run towards the barn. They’re intrigued and scared by the dark interior, but Perfecto (Petra’s partner) soon arrives and scolds them for venturing inside a potentially unstable building.
In a series of flashbacks, Estrella and Petra reminisce about Estrella’s biological father, who abandoned the family years ago. Estrella has few memories of her father, but the strongest one involves him expertly peeling an orange for her during a long drive like the one they’ve just finished. It’s a comforting moment, but when he goes to work in Mexico and eventually loses touch, Estrella’s life becomes marked by instability, unpaid bills, and hunger.
Petra suspects that her husband is going to leave long before it happens, but she’s powerless to do anything to prevent it. When he finally abandons her, she’s overwhelmed by the task of feeding five children on her meager wages. She’s almost envious that he gets to start his life over again, while she is forever tethered to her children. During this period Petra is often distracted and tense, and Estrella takes on much of the responsibility for the children; she makes up games to distract them from hunger. One day when the children are making too much noise Petra shouts at them; taking charge of the situation, Estrella reprimands her mother and does a funny dance for the children with an empty box of Quaker oats.
Estrella also remembers the first time she met Perfecto, Petra’s partner of several years. She was initially suspicious of the tool chest he carries everywhere, but the older man has now taught her the functions of all his tools. She realizes that working with his hands gives Perfecto a kind of power – much like the power of reading, which she’s tried to learn during her sporadic intervals at school. However, most of the teachers are too impatient with her unkempt appearance and irregular attendance to put much effort into teaching her.
Estrella’s mind floats to her strongest childhood friendship, with a girl named Maxine Devridge. Maxine is from a family of white migrant workers known for rough behavior and even crime. She has a large stash of comics stolen from her brother, but she can’t read, so she relies on Estrella to interpret them. The girls often meet after work to lie in the shade of a tree and share comics, but one day, Maxine makes a rude joke about Perfecto and Petra’s sexual relationship and Estrella starts a fistfight. In punishment, the foreman fires Estrella’s family, but he allows the Devridges to stay.
Finally finished picking peaches, Alejo brings a sack to Estrella and Petra on his way home. He explains that he’s from Texas and has only come to California to work in the fields for a summer. He’s entranced by Estrella’s looks and her sense of ease in her body.
The next day, Estrella and Alejo are working near each other in the fields. She thinks of the contrast between the grueling work she performs to dry grapes and the smiling, elegant woman on the raisin boxes in the supermarket. She remembers lying on top of her mother’s sacks of cotton as a small girl; now, she has to keep an eye on her younger brothers, who are thirsty and tired in the hot sun. Unaccustomed to this rough work, Alejo is having trouble; he comforts himself by thinking about going to high school and eventually college, where he wants to study geology.
After work, Estrella walks to a nearby baseball diamond and clandestinely watches a Little League game. For her, it’s a rare moment of leisure and solitude. However, a border patrol truck passes her on the road; frightened, she runs home. She expresses her anger at living under threat of deportation to her mother, but Petra reminds her that she has a birth certificate “under the feet of Jesus” to show she belongs in America.
For the next few days, Alejo makes an effort to talk to Estrella during the rides to and from work. He frequently asks about her plans for the future, which unsettles her because she feels that the only thing in her future is field work. One day, they stay out late at night to watch a lunar eclipse with the other piscadores, or field workers.
Meanwhile, Perfecto asks Estrella to help him tear down the old barn near the bungalow. She thinks he wants to undertake the project in order to make money, and is annoyed that yet another responsibility is being thrust upon her. In fact, Perfecto is becoming more and more preoccupied with returning to his hometown before he dies. He frequently dreams of his deceased first wife and biological children, and is thinking of leaving the family he has now. He wants to use the money from the barn to buy a new car battery and leave the family some extra cash.
That evening Alejo and Gumecindo are harvesting peaches as usual when a biplane suddenly sweeps over the orchard to spray pesticides. Alejo gets stuck in the poisonous mist, which burns his body and makes his insides feel like he’s on fire. Although he tries to cling to the tree branch, he falls down and blacks out, eventually opening his eyes to see his cousin’s worried face.
Estrella and Alejo, who is feeling battered and sick, spend their next lunch break huddled under a truck for shade. He tells her about tar pits, a geological phenomenon in which animal remains transform into oil over thousands of years. Gently, he kisses Estrella’s hand. At the end of the day, she retreats to the cool, dark barn to think about this new development in her life.
After his encounter with the pesticide spray, Alejo soon becomes too sick to work in the fields, and his cousin doesn’t know how to take care of him. Despite Perfecto’s reluctance, Petra takes him in, feeds him, and tries to use folk remedies to cure him. At night he sleeps next to Estrella and the children. Although he’s weak and in physical pain, he’s happy to be near Estrella and relieved that if he dies, he won’t be alone.
In a flashback, Petra remembers the first time she met Perfecto. She’s walking to the grocery stores with all her children in tow. They have to cross a large highway to get there; she and Estrella show the frightened younger boys how to evade the cars. Next to the grocery store they see a shiny car idling in the parking lot; Petra envies its owner, thinking that his life must be full of ease and simplicity. Inside the store, Perfecto is repairing the plumbing in exchange for some produce. When Petra inspects the selection of garlic, she finds Perfecto looking through the same bin. They exchange remarks on the vegetable’s beauty and pungency, and Petra thinks to herself that this is trustworthy man. On his way out he gives the younger children some ice cubes, a rare treat.
In the present, Petra wakes up huddled next to Perfecto. She can hear Alejo and Estrella whispering on the other side of the dividing curtain. He talks about the future and asks what grade Estrella has reached in school. Eventually, she hears them moving to hold each other. Petra’s hand wanders over Perfecto’s body, but he pushes her away.
Petra goes outside to make the family’s breakfast. She’s disturbed by how quickly Estrella is growing up; soon she’ll be old enough to repeat her mother’s mistakes, and there’s nothing she can do to stop it. That day Petra takes Alejo out to the porch, worrying about his failure to recuperate. She’s no longer working in the fields, since her legs have become so swollen recently that it’s hard for her to walk far. In the afternoon she feels sick and vomits behind the bungalow; this event confirms her growing suspicion that she’s pregnant again, and the thought dismays her.
Estrella tells Perfecto that she will help him with the barn if he agrees to take Alejo to the doctor and pay for the visit. He agrees, and the next day they load everyone into the car, but the tire gets stuck in mud before they even leave the bungalow. After spending most of the afternoon digging it out, they arrive at the clinic in the evening. There’s no doctor there, only a cloyingly sweet nurse who’s eager to go home and disappointed to see them. Since neither Petra nor Perfecto speak English, Estrella has to translate everything the nurse says. After examining Alejo, she merely tells them he has dysentery and instructs them to go to the hospital. Perfecto, Petra, and Estrella are dismayed when she charges them ten dollars for this unhelpful visit, but they give her $9.07 – everything Perfecto has in his wallet.
Walking out to the car, Estrella feels overwhelmed and panicked. They’ve squandered their money at this useless clinic, and now they can’t even afford gas to get Alejo to the hospital. Guided by instinct, she retrieves Perfecto’s crowbar from the trunk, walks inside, and threatens the nurse until she returns the money. Then the family hustles Alejo into the car and quickly drives away.
Dimly aware of what’s going on, Alejo is upset that Estrella committed a crime on his behalf, but she impatiently tells him not to worry about it. At the hospital, she takes him inside while the others wait in the car. He wants her to stay with him, but she has to go outside before Perfecto runs out of gas. She says goodbye to Alejo and returns to her family, not knowing if she’ll ever see him alive again.
When they arrive at the bungalow, Perfecto stands by the station wagon, wondering whether he should leave the family and if the battered car will last long enough for him to do so. Sensing his restlessness, Petra goes inside and makes an offering before her icon of Jesus, under which she stores the children’s birth certificates and other important documents. However, when she stands up the icon falls, and the head breaks off.
Feeling stifled and anxious, Estrella runs out of the house and towards the barn. She climbs the massive chain that hangs from the ceiling, forces open the trap door, and emerges onto the roof. There she stops and stares out at the land, hoping that her heart is “powerful enough to summon home all those who strayed.”
