In 1957, when second-graders Bryce Loski and Julianna "Juli" Baker first meet, Juli knows it's love, but Bryce isn't so sure. Girl-phobic and easily embarrassed, young Bryce does everything he can to keep away as much as possible from Juli for the next six years, which isn't easy since they go to the same school and live across the street from each other. When they start the sixth grade, Bryce hopes that he can get rid of Juli so he asks the girl Juli hates the most, Shelly Stalls, out on a date. This plan of Bryce's works for a while up until his best friend, Garrett, takes an interest in Shelly and tells her the truth about Bryce asking her out. Juli finds out Bryce and Shelly break up; she goes back to her regular Bryce-obsessed self.From Juli's point of view, when she and Bryce first met, he returned her feelings but was just shy and embarrassed. When he "held her hand" she thought she would get her first kiss from him in the second grade. Juli knew that she was flipped from then on. After finding out that Bryce and Shelly broke up, she thought she could have her old Bryce back. She spent the whole year smelling his watermelon-scented hair and wondering if she'd ever get her kiss.In 1963, now in seventh grade, Bryce's grandfather Chet Duncan moves in with the family. Chet finds Juli different, special, and a rare kind of girl who's hard to come across. He continues to tell Bryce this with hope. There's a large, old sycamore tree that Juli loves which no one understands. One day, it's cut down by the owner in spite of Juli's protest and dismay. Her voice narrates her love for the tree that let her see the world in a much more enlightened way.Chet and Juli form a strong friendship over time while he helps her work on her messy lawn. Bryce begins to develop feelings for Juli just as Juli begins to question her feelings about Bryce. Her feelings completely disappear when she overhears him and Garrett talking about her mentally challenged uncle, and sees him throwing away the eggs she gave him. Juli tells Bryce she never wants to speak to him again when she and her family get invited to the Loski's house for a sit down dinner which ends up with Bryce's dad being considerably rude to her family. At the dinner she confronts him about what Bryce said about her uncle and tells him she doesn't want to speak to him again, not ever. During dinner, they sit opposite each other, she never talks or makes eye contact with him. After dinner she apologizes for the way she acted. Bryce is upset that she apologizes, because that means that she doesn't care enough to hold a grudge.She continues to have mixed feelings when the basket boy auction is just around the corner. She hears that Shelly is planning to bid on Bryce against another one of the school's "finest" girls. Bryce thinks that Juli is planning on bidding for him because he hears she walked in with a wad of cash (which she wasn't planning on having with her). Bryce begins to worry about what would happen if she does bid for him just when she bids all her cash on basket boy number eight, the boy before Bryce.Later, during the basket boy bidding lunch, Bryce and Shelly sit at a table across from Juli and basket boy number 8, Eddie Trulock. She's facing Bryce and he can't help but stare at Juli the whole time. He sees she's having a good time with her date and gets jealous. He grabs her to talk to her and attempts to kiss her in front of everyone. He chases her after she dodges his kiss. Juli gets on her bike and cycles as fast as she can home. Garrett chases after him, and the two break off their friendship after a confrontation.Juli bikes home crying. Bryce continuously tries to talk to her, ringing the doorbell, calling her house, coming to her bedroom window, despite her ignoring him. Finally, one day Juli sees Bryce digging a hole in her front lawn which infuriates her. Her father said he gave him permission and she watches Bryce continue to dig. After he digs the hole, he leaves. Juli is confused but Bryce comes back carrying a baby Sycamore tree and places it in the hole. She goes outside to help him. Knowing that he redeemed himself, Bryce covers Juli's hands with his, they share smiles and then continue planting the sycamore tree.