Mika is an average high school girl who has yet to experience true love. She runs into Hiro, a rebel with bleached-white hair in between classes but was instantly put off by his unusual look and demeanor. Mika loses her cellphone the next day only to find it in their school library with all her contacts deleted. Then receives a call from a mysterious guy in the library, the guy claims to have found her cellphone from then on the mystery guy continues to call her every day even buggin her at night all through out their school break, wooing and wowing her with his witty banter and slowly Mika is won over by the mysterious guy. Finally, on the last night of their school break which also happens to be Mika’s birthday her mystery guy after singing Happy Birthday asks Mika to meet him in person by the pool before their school assembly.
The next day Mika is shocked to learn the mysterious guy turns out to be the punkish white-haired kid she ran into before. At first she thought that they weren’t suitable for each other since both of them led different lifestyles, but it doesn’t take long before they become a couple and more. Tragedy soon strikes when Mika is raped by three guys hired by Hiro’s ex-girlfriend, Saki, who is jealous of his new found love. Hiro was extremely mad about this incident and avenged Mika on her perpetrators. This tragedy only strengthens Mika & Hiro’s bond and makes their relationship much stronger. Few months later, Mika becomes pregnant with Hiro’s child. The teenage couple decided to have the baby and asks for their parents’ blessing on their plans of getting married.
Things turn for the worse again during a confrontation with Hiro's ex-girlfriend Saki, Mika falls on her humps, later that daywhile happily strolling with Hiro on Christmas eve she had an unexpected miscarriage, ('twas pretty heart breaking because while Mika was in the OR, Hiro run off to the temple and prayed out in the cold --- snow and all). The next semester, Hiro inexplicably gives the cold shoulder to Mika and deliberately ignores her at all costs. She even finds him kissing another girl at a house party Hiro was hosting, in which she only learned about through her friend Aya. When Mika confronts Hiro about his recent behavior, Hiro tells her that he wants to break up because he wants to start seeing other girls. The devastated Mika desperately tries to get back with him but ends up wallowing in isolated misery. Later Mika attends a Christmas party with her friends and some college guys. There, she meets a nice guy named Yu Fukuhara and Mika finds herself slowly opening up to Yu. On December 24, Mika and Hiro meet again after a very long timeat the place where they agreed to annually come to commemorate their baby girl's death and that was the first time Mika noticed he was wearing a hat and Hiro told Mika that's his new style now.
The next winter, instead of Hiro, Hiro's friend Nozomu shows up and tells her that Hiro was diagnosed with cancer and that was the reason why he dumped her. Mika runs to the hospital and promises Hiro that she'll never leave him again. Her relationship with Yu ended there. Hiro and Mika have a wonderful time for a while; they even exchanged marriage vows while on a picnic on Hiro’s favorite spot. Sometime later Hiro asks Mika to print out some pictures for him. While she does that, she receives a phone call from Minako telling her Hiro is in a really serious situation. Mika runs and then fell flat on the floor and the pictures scattered everywhere. Surprisingly, all the pictures were of Mika when they got back together, Hiro was secretly taking her pictures while she takes care of him in the hospital. She then calls Hiro’s phone and Minako answers, so via video call she asks Hiro to open his eyes and wait for her because she’s on her way. Hiro then asks her to smile and after Hiro saw Mika smiled at him even while she was crying Hiro died while they were still on video call.
Later, Mika tries to kill herself by throwing herself off a bridge, but two doves came out of now here then she freaks out, causing her to jump backwards and ends up not killing herself. She was holding Hiro's journal, and the journal magically opened to the page where he drew a picture of him, her, and their baby girl and while she browse through his journal it seems that all entries of Hiro was about her.
The movie returns back to the present, Mika was remembering Hiro while on the train going home to visit her sister and parents, she meets up with them at the train station this was probably around 5-7 years later from the time she met Hiro and up to that day she continues to loves the Sky (Hiro wants to be a Sky because he wants to be able to watch Mika from above and immediately know if she's in trouble) and all the memories of Hiro is still very vivid on her mind.
Author Note: To those who have not seen this movie, KOIZORA-sKy oF lOvE, a Japanese Sad Love Story, I hope the summary I made would encourage you to give a shot and to those who have seen it, I sincerely hope that I gave justice with my summary.