Arizona. 17-year-old Temple Grandin arrives at her Aunt Ann’s ranch the summer before attending Franklin Pierce College. It soon becomes clear that the girl relates to animals better than she does people (she recoils when Ann tries to hug her). To counter Temple’s fear of her new bedroom, Ann makes a sign that says “Temple’s Room,” that reassures the girl. But when the sign accidently falls off her door, it sends Temple into a panic that is soothed when she enters the outdoor cattle restraining machine, which works like a hug without human contact. Temple ends up settling comfortably into her ranch life – until Eustacia arrives to take her to college in New Hampshire.
In a flashback, Eustacia is told by a psychologist that 4-year-old Temple suffers from infantile schizophrenia and autism, and may never speak, recommending that Temple be institutionalized. Eustacia refuses, deciding to home-school her daughter. In the present, to quell her classroom panic and fear of sliding doors, Temple builds a homemade version of the cattle restraint, or “squeeze machine.” Deeming it “sexual” in nature, the campus psychiatrist, Dr. Spenk, has it destroyed.
Back on the ranch for spring break, Temple makes a more sophisticated version of the squeeze machine. Refusing to return to college without it, she and her aunt discuss its use with Dr. Spenk. Temple proposes a scientific experiment to Mr. Neal, head of Psychology, to survey students’ reactions to being in the squeeze machine, but becomes overwhelmed by the data she has accumulated and misses her presentation deadline. After receiving an “F,” Temple places a frantic call to Dr. Carlock, her science teacher from high school. We flash back to 14-year-old Temple and Eustacia meeting the staff at the Mountain Country School, where Dr. Carlock sees Temple as a unique individual who could do well there. Other students target her with taunts, but she finds comfort in a high-strung horse named Chestnut, whose eventual death leaves her wondering where animals go when they die. Dr. Carlock understands that Temple’s mind works differently and offers to mentor her, urging Temple to go through the next “door.” Since she thinks in pictures, Temple literally sees doors in her mind.
Back at Franklin Pierce, Temple convinces Mr. Neal to look at her paper, and is assured it will receive a good grade. She is allowed to stay at the school, and is permitted to keep the machine as long as her new roommate Alice, who is blind, agrees. Bolstered by the new friendship, Temple confidently participates in school. In a fast-forward to graduation, Temple addresses students and their families, offering an off-key rendition of “You’ll Never Walk Alone” as her mother watches, full of emotion.
Studying for a Masters at Arizona State, Temple is confronted at a Scottsdale feedlot by Don Michaels, a dismissive cattle boss. Undeterred, she focuses on cows mooing as they are led to the dip vat, and notices a pattern. She decides to write her thesis on mooing as an indicator of cattle behavior. Though it is initially rejected by Prof. Shanklin, she convinces him that her autism enables her to visualize what causes panic in animals and understand how to prevent it, which can lead to better business.
Needing Don to sign off on her paper, Temple runs into another obstacle: women aren’t allowed on the lot she needs to research. So she disguises herself as a man, gets a pickup truck, and makes it past the security guard. After falling victim to the childish pranks of several cowboys, Temple is befriended by Randy, Don’s right-hand man, who signs off on Temple’s thesis in place of Don.
At a cattle auction, Temple pitches her ideas to Jeff Brown, editor of Arizona Farmer Ranchman magazine. She stuns Prof. Shanklin by informing him that the feedlot signed off on her study, and she has a published article on cattle agitation in the magazine. Returning east for Christmas after completing her Masters, Temple is overwhelmed by the social scene and has a panic attack, but is reassured by Eustacia. Back in Arizona, she faces with a familiar problem when she’s denied admission to the Scottsdale feedlot. Aided by a press pass and a more presentable appearance, Temple returns to the lot to write articles. Another feedlot owner, Ted Gilbert, hires her to come up with a design plan for his new cattle dip, but gives her just five days to do it. Her plan for serpentine curves and other features designed to keep cattle calm is deemed “a masterpiece” by Red Harris of Cattle Magazine, but her design is corrupted by a clueless cowboy, leading to the deaths of three cattle. Outraged, Temple flees to Dr. Carlock, who advises her to build her own slaughterhouse.
Later, Temple learns that Carlock has died. At the funeral, Eustacia tries to explain the concept of grief to the girl, but Temple instead correlates it with the last time she said goodbye to her mentor.
Fast forward. Temple is in a supermarket, again intimidated by sliding glass doors. She is helped by a kindly stranger, Betty Goscowitz, a fortuitous meeting that proves instrumental in helping her gain access to the Abbot slaughterhouses where Betty’s husband works. Temple subsequently pitches her ideas to the Abbot board, and her designs are adopted. She proudly shares her success with Alice. At the National Autistic Convention in Denver, parents argue with experts about how autism should be treated. Suddenly, Temple stands and addresses the crowd, telling them that she will always be autistic, and that her ability to function in the world today is due to the encouragement of her mother and others, who recognized her gift of seeing the world in a new way.