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.
在我生命的大部分时间里，我在屏幕上经历了沧桑，但我已经走过了岁月，却无法在镜头前表演片刻的告别。当剧组停止拍摄时，资深演员去蓝色海岸看望他们的老朋友。
《后街女孩》的故事描绘了三个黑社会组织的流氓，山本健太郎、里原龙树和杉原和也。由于他们的错误，该组织的领导人命令他们转变为女性偶像歌手，为老板赚钱。三人本来想拒绝，但接受了这个条件，因为他们不想死。但是没想到他们成为偶像歌手之后，真的是火了，拥有了很多粉丝！但他们心中仍然有钢铁侠，每天都很痛苦。
