Earth. The not too distant future. A city is miraculously reborn just sixteen years after being completely destroyed by a giant meteor. At the prestigious Graviton High School for Girls, two new students are introduced. A-ko and her ditzy sidekick, C-ko.

U.C. 0123. After a generation of peace, the Earth Federation has begun to build new space colonies to house humanity's growing population. But a new force, the aristocratic Crossbone Vanguard, plans to seize the colonies of the newly constructed Frontier Side for itself. As their home becomes a battlefield, a handful of young civilians struggle to escape the conflict. To save his friends and family, the reluctant warrior Seabook Arno becomes the pilot of a new Gundam which bears the code name F91.

Seikima II was a real-life Japanese death-metal band. Full of kabuki makeup, songs about rape, murder, and satanic destruction, and a public persona of devilish evil. The OVA purports to tell the backstory of the band, which, according to its publicity, was composed of actual demons (akuma) from the parallel dimension Makai. In the OVA, five vicious demons (the five band members), led by Demon Kogure (the lead singer), are plotting the destruction of humanity. The only effective opposition comes from the saintly Rosa, who is actually the reformed war goddess Freyja in disguise. The demons attempt to activate their ultimate weapon, the Tower of Babel, before Rosa can complete her counter weapon, the Tower of Cain. The demons triumph and are on the verge on destroying the world when their leader suddenly decides that they should, instead, form a rock-and-roll band in order to convert people everywhere into demon worshipers.

A-ko and B-ko are fighting as usual, as C-ko watches from the sidelines feeling neglected by both. Ayumi-sensei has been behaving strangely lately. She's wearing a heart-shaped crystal with a hexagram inside, and is chanting mysterious prayers in private. At the ruins of an ancient civilization, an archaeologist spies a hexagram among the hieroglyphics. Deep in outer space, an alien fleet is on a course for Earth, and its flagship bears the same hexagram shape.

Based on the real sports team Hanshin Tigers baseball team and their victory at the national professional championships.

A class of Japanese youths volunteer for the war effort during WWII, but then get stranded in Manchuria.

Three weeks have gone by since the alien spaceship crash landed on the Graviton City spire, and since then the aliens have been hard at work converting their ship to a pleasure district, hoping to make friends with the humans!… Not. Perpetually late and continually over-eating A-ko, spacy and cheerful C-ko, and brilliant and bold B-ko are about to enter summer break from school, and it just so happens the alien ship is open for business. When a free meal turns into a sob story about how the aliens just want to go home, will it be A-ko or B-ko who can get the ship into orbit again?