A tale of delinquent and lazy school girls. In their efforts to cut remedial summer math class, they end up poisoning and replacing the school's brass band.

Graduation draws near for Yui, Ritsu, Mio and Tsumugi, the four 3rd-year students of the Light Music Club. They, together with Azusa, decide to go on a post-graduation trip. Their destination, decided by Lot, is London!

For teenage misfits Hunter and Kevin, the path to glory is clear: Devote themselves to metal. Win Battle of the Bands. And be worshipped like gods.