The events of the novel take place in one day. Less than eight hours, actually.
Leticia arrives at school, ready for her zero hour geometry class that she has to take for credit recovery. Trina comes early to finish an art project and bask in her own talent. And Dominique, who has gotten below a seventy-five in one of her classes, has come to school to try to talk her teacher into raising her grade.
Leticia escapes Geometry to try to get some gossip, and she sees Trina passing too close to Dominique in the hallway before school starts. Dominique is in no mood to cut Trina slack, though, because she has just been shut down by Coach when she asked for her minutes on the court back. So, in front of her two friends and a hidden Leticia, Dominique looks at Trina's back and vows to beat her up after school.
Aware that she has just witnessed some serious dirt, Leticia calls her best friend, Bea. And then Bea tells Leticia to tell Trina—you know, to warn Trina—but Leticia waffles. It's not her business, she thinks.
The day continues for all three narrators. Dominique goes to Social Intervention class and remains upset about Coach benching her and Trina getting too close in the hallway. Leticia goes to English and French, where she tries to do as little work as possible. She even tries to get the secretary to change her schedule, but no dice. And Trina does her Trina thing in her classes, imagining that everyone wants to either be her or be near her, thinking about how great an artist she is.
In gym class, Leticia's nail breaks and she calls her parents to intervene. Her mother refuses, but her father comes and does what Leticia asks. (Big clue as to why Leticia is the way she is.)
The next time all three narrators are in the same room is at lunch in the cafeteria. Trina stomps uninvited with the popular Boosters, and while she's up there, Dominique reasserts her intention to beat her up. And after Trina jumps in with the Boosters, Leticia decides that she's going to just mind her own business and not tell Trina anything. Decision made.
After lunch, tension in the school hallways builds about the possible fight. Leticia starts to feel more and more agitated about whether she should tell Trina, so much so that she can't concentrate in her classes. Dominique asks Coach one more time to put her in, but Coach refuses. And Trina goes to art class where she and Ivan draw one another's portraits.
When the bell rings, Leticia is swept outside with the crowd of students who are following Trina. Dominique attacks Trina, and when a female cop pulls Dominique off, Trina isn't moving. The ambulance comes and takes Trina away. When the assistant principal asks if Leticia knows anything, Leticia says no and goes to her nail appointment.
Ivan visits Trina in the hospital and tells her that the teachers and students at school are rooting for her. Trina is still in a coma.
Months later, Leticia catches a spot on television about girl-on-girl violence, and she recognizes Dominique, who has no regrets. Then Trina and her mother appear in shadow, and Leticia and Bea comment on how Trina's different after all the surgeries. Bea has to go get ready for a date, and Leticia wishes that she could have been on television.