The film is told from the alternating points of view of Bryce (Callan McAuliffe) and Juli (Madeline Carroll), two eighth-grade kids during the 1960s.
Juli has really strong feelings for Bryce, however Bryce doesn't want anything to do with her. Throughout the course of the film, these opinions are flipped as Juli begins to like Bryce less, while he begins to develop feeling for her.
One day Bryce tries to kiss Juli in the school cafeteria and she runs home and locks herself in her room, totally ignoring Bryce. A few days later, Juli sees Bryce digging a hole in her lawn. This initially angers her, however she notices that Bryce is in fact planing a sycamore tree (to replace a similar tree she loved climbing, which was cut down earlier in the film). With this act, Juli's feelings for Bryce returns and she goes outside to help him plant the tree.
Thanks Sean K!