At first glance the girls of Shinjugamine high school seem to be just normal everyday students, but they are in fact elite fighters trained to combat incursions by mysterious creatures called Irous. However, after having won two major battles in the past they’ve since grown complacent and sloppy… so much so that they must now undergo complete retraining.
A schoolgirl show based on a game featuring a mix of action, comedy, idols, daily life events, and minor ecchi content. While the story takes place after certain events in the game, it does not seem to be necessary to play that in order to watch this.
More Information:
aniDB
HIDIVE
Wikipedia