这部电影改编自日本作家松田诚2009年出版的同名小说。Kenichi的女儿Meiji出生后不久，他的妻子鹏子突然因病去世，留下Kenichi和Meiji相依为命。妻子的父母建议他再婚，并想在他身边抚养孙女明治，但健一仍然决定自己照顾女儿。
The story of the movie is somewhat based on the plot of the most recent game, "Sakura Wars 3," released back in March this year. While the game features Lieutenant Ohgami, the main character who takes off for Paris, narrates one side of the story, the movie unveils the secrets behind Hanagumi. Ohgami leaves for Paris, consequently leaving Hanagumi without a leader; thus a new character will be introduced here. To be replaced with Lieutenant Ohgami is the former leader of Hoshigumi, Rachette Artile - a rationalistic and distinct individual, who brings about serious problems to Hanagumi. The members are now in discord with Rachette. Meanwhile, Teikoku Kagekidan was being threatened by some irrelevant demons and a new type of anti-kouma mechas, (brought by an american company) appears and tries to replace the koubu-kai. Having made repeated mistakes due to the absence of Ohgami, Hanagumi is now faced with an unprecedented danger, while the abolishment of Teikoku Kagekidan Hanagumi is being schemed.
