The Rift between the present world and the another world caused by the instability of energy is the only passage to the present world for the monsters in another world. In order to block the invasion of monsters, in the present world, a group of people with special power bravely stand in the Rift to defend the world.

Mika Katagiri wants her band to perform at the upcoming local festival. However, complications arise. Their keyboardist, Jun, refuses to play, and their stage has been cancelled. Refusing to give up, Mika and her band strive to find a way to play at the festival, using any means necessary.

A 2D remake of Nagao Takena's original claymation Nendo no Tatakai.

The OVA, bundled with the special edition version of the seventh manga volume, will tell an "other side" story centered on Mafuyu Satou and Ritsuka Uenoyama that wasn't featured in the movie.