The movie is set during recent times in which there are a large number of Afghan refugees living on the outskirts of Tehran. Almost a silent movie, Baran won a number of awards both nationally and internationally for the director and writer Majid Majidi.
It is winter in Teheran. Lateef is 17. He works at a building construction site managed by MEMAR, the site foreman. Lateef's job is to serve tea and prepare food for the workers with whom he is always quarrelling. The workers come from all parts of Iran. Some workers are Afghan refugees from war-torn Afghanistan. They have no identity cards and are employed illegally as cheap labor. When the labour inspectors show up, the Afghan workers must hide.
As the story starts, an Afghan worker, NAJAF, falls from the building and breaks his leg. He is taken to the hospital. The next day, SOLTAN, another Afghan worker, brings in RAHMAT, Najaf's son, who is around 14 years old, to replace his father. Memar soon realizes that Rahmat is not fit for such hard work, and decides to switch the jobs between Rahmat and Lateef. Lateef is furious, threatens Rahmat, tries to sabotage his work and spies on him. One day, by looking through the door where Rahmat works, he is totally shocked to discover that Rahmat is a girl. As he watches her comb her hair, he finds himself in a strange state, surrounded by unusual sounds.
From then on his attitude changes completely; he becomes protective, helpful and gradually desperately in love with Rahmat. While Rahmat does not express herself verbally at all, over time she seems to respond to this love. During a surprise visit of the labour inspectors, they find themselves face to face with Rahmat. She panics and runs away, as they chase her through the city streets. Lateef runs after them, struggling with the inspectors while Rahmat flees. Lateef is beaten and taken to the police station. Now Memar must pay a fine, comply with the law, and lay off all illegal Afghan workers.
Lateef can't bear Rahmat's absence, and decides to locate Soltan to get some news of her. He goes to the village where the Afghans live, walks around, meets an enigmatic cobbler, and ends up in the courtyard of a shrine near a graveyard where Afghan families are gathered for a local milk ceremony. He inquires about Soltan, but gets no clues. Among the Afghans in the courtyard stands Rahmat in female clothing. She sees Lateef, stares at him for a while, then leaves the ceremony. Lateef is not aware of her presence. The next day on the road, he finds Soltan, and learns that Rahmat works in the village near the river. Lateef rushes there to find Rahmat in a pitiful state, working with other women carrying heavy stones from the river. He is distressed, and wants to find a way to help her out of that ordeal.
He gets all his accumulated wages from Memar, and hands them to Soltan, asking him to pass them on to Najaf. They agree to meet the next day at the shrine after Soltan has given the money to Najaf. The next day at the shrine, instead of Soltan, Najaf shows up to inform Lateef that Soltan has gone to Afghanistan. He tells Lateef that Soltan came to him and offered him some money he'd borrowed from someone. He also tells Lateef he has refused the money, and has advised Soltan to keep it for himself, and use it to leave immediately for Afghanistan where he had a life and death issue in his family. Lateef is now shocked and worried.
Lateef becomes even more worried the next day when he overhears a conversation in Najaf's house that Najaf is now faced with family problems in Afghanistan, as his brother has been killed in the war. He also hears Rahmat's real name is BARAN. Lateef goes back to the river to find Baran, who is exhausted, carrying logs out of the river in an atmosphere reminiscent of a war field. Powerless before the hardship she is going through, Lateef returns to the construction site in a state of depression. The next morning, Najaf on his crutches is at the construction site to meet Memar. Lateef overhears Najaf begging Memar without success to lend him some money.
Lateef makes a desperate attempt to get money. He sells the only valuable thing he has, his identity card. When he brings the money to Najaf, Lateef learns that thanks to this money, Najaf and his family will return to Afghanistan. Lateef is overwhelmed by this news, and finds refuge in the shrine. There, in a state of anguish and despair, he hears from all around him the same sounds he heard when he first saw Baran. He surrenders to his fate.
The next day in a dreamlike atmosphere, while helping Najaf to load a truck with household effects, Lateef, with a serene look, is finally face-to-face with Baran. Through eye contact and physical proximity, they exchange their feelings of love. As Baran covers herself and walks to the truck, her shoe gets stuck in the mud. Lateef gets on his knees, takes her shoe out of the mud, and hands it to Baran so she can wear it and leave. The truck takes Baran away. Left alone in the empty place, Lateef stares at the footstep in the mud left by Baran's shoe, and smiles while the rain