I’ll probably have to class this as a near-future SciFi film, although the focus is on the importance of family.
Summer Wars (2009) tells the story of Kenji Koiso, a math prodigy and junior at Kuonji High School. He is invited to the country for four days by a senior, Natsuki Shinohara, to celebrate her great-grandmother’s 90th birthday.
It is not until he is introduced that he finds out he is supposed to be Natsuki’s fiancé. At first he is unwilling, but Natsuki convinces him it is only for four days. That first night, Kenji receives an email with an encrypted message. It takes him most of the night, but he decrypts it and replies with the text.
The next day he finds out that his account in a virtual world called OZ, where he is a part-time moderator, is disabled. He sees a news program talking about the hacking of OZ by a young man, and showing his picture as a suspect.
The remainder of the film shows Kenji’s attempts to repair the damage and expose the true culprit, while under suspicion. On top of that, Natsuki’s great-grandmother dies, throwing the entire family into mourning.
The unusual members of Natsuki’s extended family play roles in assisting or hindering his efforts while Kenji and Natsuki gradually grow closer, against a background of the chaos caused by the hacking piled atop the family’s sorrow at the matriarch’s death.
This movie has a great story with memorable characters, although I did have some problems with names and relationships. Luckily Wikipedia’s article about this film includes a genealogical chart showing the family tree.