LouAnne Johnson, a retired U. S. Marine, applies for a teaching job at Parkmont High School in California, and is surprised and pleased to be offered the position with immediate effect. Turning up the next day to begin teaching, however, she finds herself confronted with a classroom of tough, sullen teenagers, all from lower-class and underprivileged backgrounds, involved in gang warfare and drug pushing, flatly refusing to engage with anything.

They immediately coin the nickname "White Bread" for LouAnne, due to her Caucasian appearance and apparent lack of authority, to which LouAnne responds by returning the next day in a leather jacket and teaching them karate. The students show some interest in such activities, but immediately revert to their former behaviour when LouAnne tries to teach the curriculum. Desperate to reach the students, LouAnne devises classroom exercises that teach similar principles to the prescribed work, but using themes and language that appeal to the streetwise students.She also tries to motivate them by giving them all an A grade from the beginning of the year, and arguing that the only thing required of them is that they maintain it.

In order to introduce them to poetry, LouAnne uses the lyrics of Bob Dylan's 'Mr. Tambourine Man' to teach symbolism and metaphor; once this is achieved, she progresses on to Dylan Thomas's 'Do not go gentle into that good night'. LouAnne rewards the students liberally, using candy bars, reward incentives, and a trip to a theme park. Her methods attract the anger of the school authorities, George Grandey and Carla Nichols, who try to force her to remain within the curriculum.Particular individual students attract LouAnne's attention for their personal problems. Callie Roberts is an unusually bright girl who excels at English, but is removed from the school halfway through the semester when she becomes pregnant.

LouAnne visits her outside of school hours to try and persuade her to continue with further education. Raul Sanchero is a well-meaning boy who is frequently involved in gang warfare and street crime. LouAnne tries to encourage him to focus by paying a special visit to his family to congratulate him on his work, and going to dinner with him as a way of instilling confidence and self-respect.Emilio Ramirez is her most troublesome personal project, as he believes strongly in a sense of personal honor that prevents him from asking for help.

When LouAnne discovers that his life is in danger because of a personal grudge held by a recently-released thug, she tries to protect him, but due to the cold attitude of the principal, he is abandoned at the crucial moment and is subsequently killed. At the end of the year, she announces to the class that she will not be continuing to teach at the school, which prompts an unbridled display of emotion from the students who refuse to let her leave. Overwhelmed, she reconsiders the decision.