At James A. Garfield High School in Los Angeles, California, Jaime Escalante arrives for his first day teaching computer science. However, a jaded administrator named Raquel Ortega informs him that the school never received funding for computers, and Jaime is re-assigned to teach math. His students are rowdy, and some only speak Spanish. Jaime struggles to gain control of the class. After school, he discovers his car has been broken into and the stereo stolen. Taking out the trash at home, Jaime runs into his neighbor, Joe, and surprises him with the news that he quit his high-paying, corporate job to become a teacher. One day in class, Jaime dresses up in a chef’s hat and cuts up apples to demonstrate percentages, disarming the students with his gruff demeanor and witty asides. Two gang members, Chuco and Angel, interrupt the lesson as they arrive late. Jaime asks Chuco to stay after class, but Angel returns with more gang members to intimidate him. Outside school, Jaime sees Chuco engaging in a brawl and stops Angel from joining. At the next class, Jaime forces Angel to answer a simple math question, and Angel begins to participate along with the other students. At an administrative meeting, Principal Joe Goodell announces that Garfield is at risk of being put on probation for poor academics. Jaime clashes with Raquel Ortega when he argues that students will rise to the level of expectation presented by their teachers. Back in class, Jaime passes out a quiz, and Angel leaves with Chuco. Later, Angel admits he wants to study, but he cannot be seen by his fellow gang members carrying books. In turn, Jaime gives Angel three math books so that he can keep them at home and school. When a hard-working, soft-spoken student named Ana Delgado reveals that she must quit school to work at her father’s restaurant, Jaime takes his wife, Fabiola, there for dinner. After the meal, Jaime confronts Mr. Delgado, who is proud of his business and wants his family members to work there. However, Delgado eventually changes his mind, and Ana is allowed to return to school. The class takes a field trip to the computer company where Jaime’s neighbor Joe works, and Jaime is surprised to learn that Joe’s teenaged daughter studies calculus. At the next administrative meeting, Jaime announces that he wants to teach calculus so his students can take the Advanced Placement examination and earn college credit. Although Goodell is in favor of the idea, Ortega feels strongly that the students will fail and lose confidence in themselves. With Goodell’s support, Jaime teaches math over summer break so his students will be ready for calculus in the fall. Although he must teach in the school locker room with no air conditioning, the students suffer through the heat. At the start of the next school year, Jaime passes out waivers for his students’ parents to sign, allowing them to come to school one hour early on weekdays and attend on weekends. The students have a hard time conforming to the demanding schedule, and one day, Angel shows up late after taking his ailing grandmother to a doctor. Jaime, who is also exhausted, refuses to listen to Angel’s excuse and orders him to leave. At home, Fabiola complains about all the extra work Jaime has taken on, informing their two sons that their father has agreed to teach night classes for no pay. Angel shows up at the front door with his grandmother, hoping that Jaime will forgive him, and Jaime ushers the older woman in while accusing Angel of being manipulative. At one of his night classes, Jaime teaches English to Spanish-speaking adults but walks out of class when he begins to feel ill. Outside, he topples over from a heart attack. While Jaime convalesces, his students have a substitute teacher, Mr. Schloss, who knows nothing about calculus. Although the doctor orders Jaime to avoid job-related activity for a month, he returns to Garfield early, helping the class prepare for the Advanced Placement examination. After taking the test, the students celebrate by going to the beach. Sometime later, test results reveal that all eighteen students passed the exam, meaning Garfield had more students pass than any other high school. Joe Goodell congratulates the class by making a special announcement, and the students present Jaime with a plaque. Soon afterward, Jaime learns his students are being investigated for cheating. Dr. Ramirez and Dr. Pearson of the Educational Testing Service question the class, but no one admits to breaking any rules. Jaime finds a fake letter of resignation someone slipped inside his schoolbooks and discovers his car has been stolen from the school parking lot. After walking home, he laments to Fabiola that the students have lost confidence. Angel appears outside, and Jaime is heartened to see that Angel stole his car only to fix it up. Jaime confronts Pearson and Martinez, who suggest that his students re-take the test. Jaime contends that the students were targeted because of race and socioeconomic status, but Pearson claims there were uncannily similar mistakes made on multiple tests. Even though Jaime does not want to comply, he encourages the students to re-test and helps them study with only one day’s notice before the exam. When the new tests are scored, Jaime and the students are redeemed by another set of excellent scores, with all eighteen students passing a second time.