My Sweet Orange Tree begins with José Mauro de Vasconcelos (Caco Ciocler) receiving an edition of his finished novel. Then, the film starts to tell the story from the writer's memories, through flashbacks. Zezé (João Guilherme Avila), a boy of eight years who lives in Minas Gerais in a very humble house with his family, consisting of his father (Eduardo Dascar), an unemployed and alcoholic, and his mother (Fernanda Vianna), which works to support the home and his brother and sisters. Despite the lack of understanding, affection and the aggression suffered by from his father and school colleagues, the boy has a great skill for storytelling using his imagination. With financial difficulties, the family has to move. At the new home, Zezé finds an orange tree, which he talks everyday. However, for being extremely extrovert he got involved in several confusions. One of them, he tries to ride on the bumper of Manoel Valadares, the "Portuga" (José de Abreu), but is caught and spanked. The boy feels humiliated and wants revenge, however Valadares ends up understanding Zezé, which turns to share his world of fantasies, and a new friendship arises.

Brezilya'da geçen hikayede sekiz yaşındaki küçük Zezé'nin hikayesine konuk oluyoruz. Zezé şehir dışında bir kasabada, oldukça büyük ekonomik sıkıntılar çeken bir ailenin çocuğudur. Son derece hassas ve olgun olan Zezé'nin en sevdiği şey hayalgücüyle başbaşa kalıp yeni hikayeler üretmektir. Yeni taşındıkları evde karşısına çıkan portakal ağacı ise tam anlamıyla sığınabileceği tek varlık olur. Karşısına çıkan zorlukları aşabilmenin tek yolu portakal ağacının dallarının altındadır; bu ağaç güvenebileceği, sırlarını, korkularını ve sevincini paylaşabileceği tek şey olmuştur artık.