19世纪的英国，名门贵族凡多姆海威家的执事塞巴斯蒂安·米卡利斯跟随着13岁的主人夏尔·凡多姆海威作为“女王的番犬”每天都背负着黑社会的肮脏工作。 有天，在一次煞有介事的私语中他们得知了关于「死者复生」的传闻。
然而，与她对他人漠不关心的态度相反，她对书籍抱有非凡的热情，对旧书有着非凡的了解。无论是什么谜团或秘密，只要与旧书有关，她都能解开。这是一个关于“旧书与秘密”的故事
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.
