One morning in 1970s Washington, D.C., a sixth grader named Dee lines up to enter school behind her new classmate Osei, the only Black student in the school. Ignoring other students’ racist whispers, Dee chats and laughs with Osei. When school bully Ian sees Dee and Osei laughing together, he furiously disapproves. Meanwhile, Dee’s best friend and Ian’s girlfriend Mimi notices Ian’s fury. Realizing she doesn’t want to date him if he reacts so badly to laughter, Mimi wonders how to break up with him. As the children walk into class, Osei asks for Dee’s help: his mother sent him to school with a girly strawberry pencil case that once belonged to his sister Sisi. If other children see the case, they will mock him. When teacher Mr. Brabant asks Osei whether he brought adequate school supplies, Dee sneakily hands Osei her Snoopy pencil case, which he holds up instead of the strawberry one. Afterward, Dee and Osei permanently trade pencil cases.
At morning recess, Dee’s friends Mimi and Blanca gossip about how Osei had Dee’s pencil case. When Dee joins them, Mimi asks how Osei got Dee’s pencil case. Dee explains she traded it to him for a strawberry pencil case. She gushes about Osei. When Mimi jealously points out that Osei is Black and thus “different,” Dee snaps that she likes Osei’s difference—and that she didn’t judge Mimi for dating Ian.
Also at recess, Osei joins the boys’ kickball game. He expects one of the two captains, Ian and popular Casper, to pick him last, but Ian picks him quickly. When some boy loudly questions Ian’s judgment, Ian asks whether Black people aren’t supposed to be good at sports. Osei retorts that he is good at sports—and resolves to play well. When it’s Osei turn at the plate, he kicks the ball so hard it soars over the playground fence, which earns the other kids’ admiration but also, per the teachers’ rules, means the kids can’t play kickball for the rest of recess. Dee, happy about Osei’s kick, runs up and hugs him—causing other students to burst out in racist whispers. Dee asks Osei to come sit with her in the sandpit. There, impulsively, she strokes his skull, which she tells him has a lovely shape. In response, he touches her face and tells her she’s lovely. Mr. Brabant furiously blows his whistle and chastises Osei for “inappropriate” touching.
As recess ends, a boy named Rod complains to Ian about Osei, a Black boy, touching Rod’s crush Dee. Ian suggests that they should manipulate Osei into hating Dee. Later, as lunch begins, Ian catches Mimi in the hall and orders her to find an item that Casper, Blanca’s on-off boyfriend, has given Dee and bring it to him. Mimi, thinking that Ian might agree to break up if she obeys, agrees. When she sees the strawberry pencil case fall from Dee’s backpack as Dee rushes to have lunch at home, she picks it up.
Toward the end of lunch, students go play on the playground, including Osei and Ian. Ian points out to Osei that Dee has returned to the playground from home—and that she is sharing strawberries from her mother’s garden with Casper. He insinuatingly advises Osei to “keep an eye on” Dee and Casper. When Dee spots Osei, she rushes over and offers him some strawberries. A jealous Osei claims not to be hungry, though he later relents and tries one. Ian gloatingly thinks how enjoyable he’ll find it to wreck not only Osei’s life but also the lives of super-popular Dee and Casper.
Ian instructs Rod to insult Blanca, hoping this will push Casper to hit Rod in reaction. Then Dee will defend Casper to Osei, making Osei jealous. Soon enough, Casper has punched Rod. Mr. Brabant grabs Casper, and another teacher (Miss Lode) takes Rod to the nurse’s office. Blanca reveals to Mimi and Dee that Rod said she was a “trashy” girl who let Casper have sex with her. Ian saunters over to the girls and says it’s a shame Osei is wondering about Casper’s character now. Dee, thinking it would be much better for Osei to befriend Casper than Ian, goes to defend Casper to Osei—which deeply annoys Osei. The students reenter class, and Dee realizes in horror the strawberry pencil case is missing from her backpack. When Osei asks her where it went, she guiltily lies that she left it at home.
As the students begin afternoon recess, Mimi offers to give Ian the strawberry pencil case if Ian breaks up with her. Ian agrees. Then Ian finds Blanca on the playground and gives her the case, claiming that it is a “secret” gift from Casper, who has been suspended. Later, Ian tells Osei that Blanca has a new pencil case that Casper gave her. When Osei sees Blanca holding the case, he realizes Dee lied to him and infers that Blanca’s boyfriend Casper must be involved somehow. He becomes furious at Dee’s lie and her seemingly cavalier treatment of the case. When Dee bounds to him at the end of recess, he yells at her to leave him alone and shoves her. She falls and hits her head. Yet when Miss Lode and Mr. Brabant rush up, Dee lies to them, saying that she tripped. The teachers tell Mimi to take Dee to the nurse’s office. Mimi, feeling guilty about the pencil case, wants to admit what happened to Dee but doesn’t. Dee—baffled by Osei’s anger—starts crying.
After Dee returns from the nurse’s office, Osei asks her to meet him on the playground after school. Dee agrees, and she arrives at the playground later to find that Mimi, Blanca, and Ian are all there. When Dee finds Osei atop the jungle gym, Osei orders her to climb it and look at the outer pocket of Blanca’s backpack. Dee sees the strawberry pencil case—and asks in shock how it got there. Osei says he knows Dee is “two-timing” him with Casper and that she gave Casper the strawberry pencil case, which allowed Casper to give the case to his other girlfriend Blanca. Osei insists that Ian is the only person willing to tell him the truth. Dee, suddenly suspicious, goes to confront Ian. Osei, furious that Dee would walk away from him, yells that she is a “whore” who “touched [his] dick” and had sex with Casper. Dee, humiliated, flees the playground. Mimi angrily confronts Osei, asking why he would lie about Dee. Osei claims he has “proof” and tells Mimi to climb up and see. Mimi begins climbing—but Ian yanks her down. She strikes the pavement hard and blacks out.
Mimi wakes, unable to move her legs. When Miss Lode and Blanca rush over, Mimi sees the strawberry pencil case in Blanca’s possession and asks whether that’s Osei’s “proof.” When Osei says yes, Mimi explains that when Dee accidentally dropped the case, Mimi picked it up and gave it to Ian, who must have given it to Blanca. Horrified, Osei asks Ian why he did what he did. Ian replies, “Because I can.” Mr. Brabant arrives on the scene and demands to know what Osei did to Mimi. Miss Lode tries to explain, but Mr. Brabant interrupts. Using a racial slur, he demands that Osei come down from the jungle gym. Osei, pushed too far, declares that “Black is beautiful” and prepares to throw himself from the top of the jungle gym.