Plot
Tomoya Okazaki is a male third-year high school student who does not feel at home anymore. He used to play basketball, his distant father works the night shift, and his mother died in a car accident when he was a child. He simply goes to school in Hikarizara for no reason and has no interest in school activities. One day, Tomoya meets a third-year girl from his school early in the year named Nagisa Furukawa. Repeating her last year due to illness most of the previous year, Nagisa is determined to graduate nonetheless. She comes up with restarting the Drama Club. By the time the sakura trees are done blooming, Nagisa has already started hand-making posters advertising the drama club's reformation, with an old group mascot called "The Big Dango Family". Tomoya and his good friend Youhei Sunohara, who used to play soccer, help Nagisa by putting them up around the school, but the student council president, Tomoyo Sakagami, and Kyou Fujibayashi, quickly go around defacing the posters and writing 'invalid' on them because of school policy. This angers Youhei greatly and he beats up one of the student council members despite Tomoyo and Kyou's warning; Tomoya takes a stand for Nagisa.
Kouko Ibuki, the teacher who had been the adviser for the drama club before it disbanded, gets involved by telling Nagisa if she can gather more members then she will talk to the school administration about re-establishing the club. Tomoya and Youhei try again, this time putting hundreds of copied posters around the school, but no one joins the club. In the end, Nagisa gets Tomoya and Youhei to sign up, and she reassures them that she will not ask them to act on stage. The drama club is re-established, and with a month left until the school festival. Nagisa decides to do a soliloquy based on a dream she has had ever since she was a child. Meanwhile, Tomoya and Youhei will work backstage with the music and lights respectively. Nagisa gets to writing the script and invites Tomoya and Youhei over to her house for dinner. Though only Tomoya comes, due to Youhei taking up a part-time job at an electrical company with Yusuke Yoshino; a former musician revealed to be Kouko's fiancé. At Nagisa's house, Tomoya meets her energetic parents Akio and Sanae. Tomoya is challenged to a baseball match with Akio to see if Tomoya's a man worthy for Nagisa, but he cannot throw the ball due to an injured shoulder he received from his father in a bad fight, and even gets to stay overnight after being heavily persuaded by Akio.
Like Nagisa, Tomoya has also had a recurring dream ever since he was a child. In his dream, he initially is disembodied in an illusionary world where he is the only thing "alive". He finds a discarded human-sized doll and uses it as a body to travel around the world on an old bicycle. After some searching, he finds a large sakura tree known as the "Tree of Promises" where he believes he will meet the person he has felt is with him in this illusionary world.
When the school festival finally begins, Nagisa reveals that she has not finished the script, but still wants to go on with the play since the story is still within her. Nagisa has her performance in the evening, so in the meantime, Nagisa hangs out with Tomoya and Youhei. During lunch, she tells them her story why she wanted to do drama was due to her parents formally having been theater actors, but they both had to give up acting after Nagisa was born. Nagisa wants to do drama so as to continue her parents' dreams in her footsteps. For the play, Sanae gives Nagisa her wedding dress to use as her costume, much to Akio's surprise. Nagisa starts with her monologue without a hitch, and during her recitation, Kouko gives stage directions to Tomoya and Youhei via headsets. Gradually, Tomoya comes to realize that the story Nagisa is reciting is the same dream that he has had, and is shocked to find that Nagisa also had the same dream of the illusionary world. At the play's conclusion, Tomoya believes that he and Nagisa were meant to be together and confesses his love to her.
Shortly after the festival, Nagisa's health falters once again and she has to take another leave of absence from school, meaning it is not until a year after Tomoya's class graduated that Nagisa is able to graduate high school as well. After this, Tomoya and Nagisa start living together in a small apartment in town while Tomoya is recruited full-time at Yusuke's electrical company as well, Nagisa works part-time as a waitress at a local family restaurant, and Youhei becomes a businessman in Tokyo. Eventually, Nagisa becomes pregnant, but her doctor informs her family and Tomoya that if she gives birth to the child, due to having a weak constitution, she may die in the process. After the meeting, they agree on telling Nagisa. Tomoya and Nagisa's parents take her to the beach where she decides the name Ushio for the child. Despite the doctor's warning, she insists that she will be fine. One winter night, Nagisa finally gives birth to a baby girl Ushio and Nagisa dies giving birth. This causes Tomoya to go into a deep depression, during which he does not go to work, or even visit his daughter who is now being raised by Nagisa's parents.
For the past five years, Tomoya's friends try to get him out of his depression, but Tomoya is very stubborn. Then one rainy night, Tomoya's father Naoyuki Okazaki comes over and tells Tomoya that he is putting Ushio in the same relationship he did when his mother died, which greatly stuns him. Later, Naoyuki requested Tomoya's friends: Youhei, Tomoyo, Kyou, Kouko, and her husband Yusuke to take him out on a retreat for a few days in order to break his depression, and they drag Tomoya out of his house so fast he does not even know what is going on. Once they tell him on the train, Tomoya is dead set on going back home but Yusuke convinces him to stay. When they arrive at their destination, Tomoya searches for another platform at the station, anticipating this, Akio and Sanae were waiting for him with Ushio. Just as Tomoya begins to walk away, his friends arrive blocking his way, then Tomoya turns around back at Ushio, she runs towards him holding a stuffed dango. She trips midway which makes Tomoya leap out and catch her. Picking her up with them smiling, he is able to see the continuation of his old dream once more, and sees Nagisa under the Tree of Promises smiling lovingly at him and Ushio.
