Sierra Shepard is a seventh-grade honor student at Longwood Middle School, a rule-following perfectionist who belongs to the school's Leadership Club and sings in the Octave, an elite eight-student a cappella choir. She notices the slightly crooked letter "R" in the banner she helped sew for the school, which reads RULES RESPECT RESPONSIBILITY RELIABILITY, a small imperfection that bothers her.
At lunch one day, Sierra discovers she accidentally grabbed her mother's identical lunch bag. Inside is a paring knife her mother uses to cut apples. Her friends react with alarm: Emma Williamson, her best friend, urges her to hide the knife, and Lexi Kruger tucks it back into the bag. A third friend, Celeste Vogel, says nothing, a silence Sierra finds unsettling. But Sierra decides the right thing to do is turn it in, since the school's weapons policy allows no exceptions. The cafeteria lunch lady escorts her to the front office, calling it "a situation." The school secretary, Ms. Lin, orders Sierra to wait for Mr. Besser, who is out all afternoon. Sierra misses her French quiz, art class, and science lab.
When Mr. Besser arrives, he is accompanied by a visiting principal. Unaware that Sierra is the student in question, he points to her as a model of his school's values. He then explains his zero-tolerance policy, declaring it means mandatory expulsion with no exceptions. When the truth comes out, Mr. Besser appears trapped, having just proclaimed his rigid stance in front of a colleague. He postpones dealing with the matter and has Ms. Lin contact Sierra's parents.
Sierra's mother, Angie, an aspiring playwright who works occasionally as a preschool substitute, rushes to the school but is turned away. That evening, Sierra's father, Gerald Edward Shepard, a prominent attorney, takes charge. He interrogates Sierra about every detail and is furious that no one told her to call her parents. He recognizes that Mr. Besser has painted himself into a corner by grandstanding in front of the visitor.
At the next morning's meeting, Gerald demands an apology and excused absences. Mr. Besser refuses, citing the signed zero-tolerance policy. He acknowledges Sierra brought the knife accidentally and acted appropriately, but insists he cannot make an exception. He announces a formal expulsion hearing for the following Friday before the district superintendent and places Sierra in in-school suspension, barred from all classes and activities.
Sierra reports to a small, windowless room, where she meets other suspended students, including Luke Bishop, a frequently-in-trouble classmate who has mocked her in the past. Despite their reputations, the students show unexpected kindness, sharing food when Sierra has no lunch. Gerald contacts reporters, and the story explodes: Three TV news vans appear, Sierra is interviewed on the local news, and her story scrolls across CNN's ticker. Gerald reports that 87 people have commented on the station's website, all in Sierra's favor. Colin Beauvoir, a boy Sierra has a crush on who sings in the Octave, tells her the situation is unfair.
Mr. Besser tells Sierra that her father's media strategy has destroyed any chance of a quiet resolution. Meanwhile, Sierra grows closer to Luke. He confides about his diagnosis of attention deficit disorder (ADD), his parents' divorce, and his mother's move to California. Sierra begins to change: When Ms. Lin snaps at them, Sierra mutters "bitch" under her breath for the first time in her life.
Colin organizes a petition with 379 student and 8 teacher signatures protesting Sierra's punishment. The Octave is then selected to perform at a major music educators' conference in Colorado Springs, but the trip falls on the same Friday as the hearing. Colin convinces several choir members to boycott the trip unless Sierra can attend. Celeste calls Sierra not to offer sympathy but to complain that Sierra's absence might ruin the trip for everyone.
Sierra's parents clash over her future. Angie takes Sierra to visit Beautiful Mountain School, a small private arts-focused school, as a backup option. Gerald dismisses the idea and insists Sierra will be reinstated. The argument deepens when he belittles Angie's playwriting as a hobby subsidized by his income, revealing tensions in their marriage.
During the second week of suspension, Ms. Lin confiscates Luke's Game Boy and vows to keep it until year's end. When Ms. Lin steps away from her desk, Sierra and Luke sneak to the front office so Luke can retrieve it. On impulse, Sierra uses Ms. Lin's open email to send a forged letter to the
Denver Post, signed with Ms. Lin's name, calling Sierra's treatment "a scandal and an outrage." She deletes the sent email and returns to the suspension room, shaken.
The
Denver Post publishes the letter. Mr. Besser angrily confronts Ms. Lin, who denies writing it. Feeling betrayed by his accusatory tone, Ms. Lin quits on the spot. Sierra overhears the confrontation and throws up in the bathroom from guilt. Her romantic hopes are also shattered when she sees Colin holding hands with Celeste.
Mr. Besser suspects someone in the suspension room wrote the letter. Luke falsely claims responsibility to protect Sierra. Moved by his sacrifice but unwilling to let him take the blame, Sierra confesses to Mr. Besser. He tells her she must apologize to Ms. Lin in person but does not cancel the expulsion hearing.
On the last morning before the trip, Sierra joins the Octave's rehearsal. When Mr. Besser arrives to persuade the boycotting members to go, Sierra addresses the choir, urging them to take the trip because she loves the choir and does not want anything else ruined. The entire choir embraces her. That afternoon, Sierra and Luke walk to Ms. Lin's apartment, holding hands, where Sierra apologizes for the forged letter. Ms. Lin reveals she hated her job for 18 years and has bought a ticket for a monthlong trip to Kenya, feeling liberated.
Gerald's research assistant has also uncovered damaging information: Mr. Besser received a charge of driving under the influence (DUI) in Massachusetts two months earlier, with a blood alcohol level three times the legal limit. Gerald plans to reveal this at the hearing. Sierra's mother calls the plan blackmail.
At the hearing before Superintendent Van Ek, Mr. Besser makes his case for expulsion but departs from his rigid stance to thank Sierra publicly for saving the choir trip. Gerald rises to present what he calls "highly relevant" information. Sierra intervenes, pulling her father into the hallway. She tells him she does not want him to destroy Mr. Besser, threatening to transfer to Beautiful Mountain and fail every class if he does. Gerald relents. When they return, he presents precedents from other districts that made exceptions to zero-tolerance policies for accidental violations. Mr. Besser, spared from exposure, tells the superintendent he can understand the grounds for ruling otherwise.
Superintendent Van Ek reinstates Sierra with no academic penalties, urging Mr. Besser to revise the policy to exempt accidental violations where students take corrective steps. Mr. Besser tells Sierra he is glad she will be back and that she can still reach Colorado Springs in time to perform with the Octave. Her mother offers to drive. As Sierra leaves, she thinks of the crooked "R" in the school's RELIABILITY banner and feels, for the first time, glad it is crooked. Everything in her life is now a little less perfect, and she finds that "completely and totally and wonderfully okay" (229).