The official website for the anime film of novelist Osamu Sōda 's Bokura no Nanokakan Sensō ( Seven Days War or Our Seven-Day War) novel revealed the film's cast and December 13 opening date on Wednesday. The cast includes:

Takumi Kitamura as Mamoru Suzuhara, the protagonist, and a loner who barely talks in school and is always reading a book. He is a history buff who knows a lot about military science, and his one pillar of support is the chat group he has with like-minded military buffs. He has a crush on Aya Chiyono, his neighbor and childhood friend.

as Mamoru Suzuhara, the protagonist, and a loner who barely talks in school and is always reading a book. He is a history buff who knows a lot about military science, and his one pillar of support is the chat group he has with like-minded military buffs. He has a crush on Aya Chiyono, his neighbor and childhood friend. Kyōko Yoshine as Aya Chiyono, a polite girl with a good upbringing who happens to be Mamoru's childhood friend. Though beautiful enough to win the school beauty contest, she always remains kind and doesn't let it get to her head. Her politician father has recently made the decision to move her to Tokyo against her will just one week ahead of her 17th birthday.

as Aya Chiyono, a polite girl with a good upbringing who happens to be Mamoru's childhood friend. Though beautiful enough to win the school beauty contest, she always remains kind and doesn't let it get to her head. Her politician father has recently made the decision to move her to Tokyo against her will just one week ahead of her 17th birthday. Megumi Han as Kaori Yamazaki, a member of the track team who hates injustice most of all. She is always worried about Aya, her best friend. Her father runs a construction business.

as Kaori Yamazaki, a member of the track team who hates injustice most of all. She is always worried about Aya, her best friend. Her father runs a construction business. Tatsuhisa Suzuki as Sōma Ogata, an easy-going guy who is the center of Mamoru's class. He is popular with the girls. He joins Mamoru's planned birthday camping trip out of interest.

as Sōma Ogata, an easy-going guy who is the center of Mamoru's class. He is popular with the girls. He joins Mamoru's planned birthday camping trip out of interest. Takeo Ōtsuka as Hiroto Honjō, a guy who was only dragged along to the camping trip by her childhood friend Saki, and is unenthusiastic for it.

as Hiroto Honjō, a guy who was only dragged along to the camping trip by her childhood friend Saki, and is unenthusiastic for it. Haruka Michii as Saki Akutsu, a girl who lives in the moment and doesn't think too hard about most things. She wants to celebrate Aya's birthday and enthusiastically joins the birthday camping trip.

as Saki Akutsu, a girl who lives in the moment and doesn't think too hard about most things. She wants to celebrate Aya's birthday and enthusiastically joins the birthday camping trip. Makoto Koichi as Malet, an 11-year-old boy who has already been hiding out in the coal factory before Mamoru and the others get there. He is an illegal alien who has been wandering in search of his family.

as Malet, an 11-year-old boy who has already been hiding out in the coal factory before Mamoru and the others get there. He is an illegal alien who has been wandering in search of his family. Takahiro Sakurai as Masahiko Honda, the secretary of Aya's father. While he carries out his duties nonchalantly, he is actually a sharp-minded man.

The mystery story and social satire begins on the day before summer vacation, when every boy in a first-year class of a downtown Tokyo middle school disappears. Was it some accident? A mass kidnapping? Actually, the boys holed themselves up in an abandoned factory on the riverbed. With support from the schoolgirls, the boys start a revolution against the adults from this "liberation zone." The new anime film shifts the settings to the year 2020.

Yūta Murano ( Brave Beats , Dream Festival! , How NOT to Summon a Demon Lord ) is directing the film at Ajia-do . Ichiro Okouchi ( Code Geass , Valvrave the Liberator , Kabaneri of the Iron Fortress ) is penning the film's script. Keishin is designing the original concept for the characters, and Hiroshi Shimizu ( Michiko & Hatchin , Megalobox ) is adapting those designs for animation.

Kadokawa Shoten published the novel in April 1985, and the novel inspired a live-action film starring Rie Miyazawa in 1988. The novel also spawned a series of print sequels and spinoffs that has sold over 170 million copies and has added new volumes as recently as last year.

Sasaki Aoko launched a manga adaptation of the novel in Kadokawa 's Monthly Comic Gene magazine on April 15, and ended it on July 13. Aoko Sasaki launched a new manga based on the film (as opposed to the original novel) in Kadokawa 's Monthly Comic Gene on August 16.