Here is a basic synopsis:
The main character is Mika. She had just started the freshman year of high school and wants to fall in love like her best friends do. Her best friend is a minor role but she helps keep the story going as she liked a boy named Nozomu. When they go to see Nozomu outside their classroom, they find him he with his blond-haired friend Hiro. Mika even asks, "Which one is it? The blond one or the black haired one?"
Her friend said, "Obviously, the black haired one." However, when they walk closer to the girls, Nozomu asks for Mika's cell phone number but doesn't get it because Mika's friend wanted it. As Mika was trying to back away as her friend was exchanging numbers, she bumped into Hiro. The two met eyes, she apologized and hurried away, and he watched her run away. Later on in the movie, she can't find her cell phone anywhere and says, "I must have it for spring break." As her friend keeps on calling Mika with her cell phone, she goes into the library to find her cell phone. She finds it but all her contacts are erased except for one unknown person on it.
Afterwards, Hiro discovers that his health is fading due to cancer. He decides to break up with Mika and hide away from her, avoiding her. He even does things like kiss other girls to push her away. However, he continues to follow her around watching over her as she moves on and meets a new boyfriend and so forth. However, when Mika finds out the truth behind the story. She leaves her boyfriend to return to Hiro and taking care of him in the hospital.
Afterwards, she is given Hiro's diary. Inside, every page was filled with her, even when they broke up, he still wrote about how she came to school with red eyes and so forth. Realizing how much Hiro loved her, she attempts suicide by jumping off a bridge. However, two white doves flew into the air, startling her and fails to jump off. As she moves away because the birds scared her, she drops Hiro's diary and sees that it has flipped to a page where he drew a picture of the two of them and a little stick figure (their baby) holding hands in the middle. She decides to move on with her life for herself and Hiro and she continues to live her life, thanking Hiro for giving her a lot of good memories also.
This was definitely worth watching and it was a beautiful love story.