The film will be a compilation film with new added footage.
Kotobukiya had originally revealed in March 2018 at the AnimeJapan 2018 event that a sequel project for the anime was in the works. The company streamed a promotional video during the event to announce the sequel project, and hinted at the introduction of the character Innocentia. Kotobukiya then stated in July that the sequel project was a film, before revealing in December that the film is a compilation film.
Kotobukiya's Frame Arms models are a line of plastic robot model kits designed by mechanical designer Takayuki Yanase (Mobile Suit Gundam 00, Muv-Luv Alternative: Total Eclipse). The new Frame Arms Girl line, introduced in 2015, features new designs by Humikane Shimada (Strike Witches, Girls und Panzer character designs), featuring robots from the original Frame Arms line portrayed as girls.
The original Frame Arms models inspired a short anime bundled with the Frame Arms Versus Set Zelfikar vs. Hresvelgr=Ater kit in May 2015, followed by a full Frame Arms Girl television anime that premiered in April 2017. Sentai Filmworks licensed the series and streamed it on Anime Network Online as it aired. Crunchyroll began streaming the series in November.
The anime's story begins when Ao opens a package that arrives at her doorstep. Inside the package is Gourai, a Frame Arms Girl: a small robot capable of independent movement. Gourai is a newly-developed prototype: a Frame Arms Girl equipped with an "Artificial Self," an advanced AI that gives her a personality. Ao is the only one who has activated her. Gourai begins to gather both battle data and emotions, starting a day-to-day life with Ao, who knows nothing about Frame Arms Girls.