Summer Wars (Japanese: サマーウォーズ, Hepburn: Samā Wōzu) is a 2009 Japanese animated science fiction film directed by Mamoru Hosoda, animated by Madhouse and distributed by Warner Bros. Pictures. The film's voice cast includes Ryunosuke Kamiki, Nanami Sakuraba, Mitsuki Tanimura, Sumiko Fuji and Ayumu Saitō. The film tells the story of Kenji Koiso, a timid eleventh-grade math genius who is taken to Ueda by twelfth-grade student Natsuki Shinohara to celebrate her great-grandmother's 90th birthday.