Subaru is a young girl who likes to see the stars. One day, she opens the door to her school's observation room, only to find a large indoor garden instead! She meets a boy named Minato who says some strange things, telling her to leave soon after their meeting. As if the day wasn't weird enough, Subaru accidentally finds a strange blobby creature who runs off with her compass, leading her to stumble into a club room with girls wearing witch costumes! Subaru recognizes her friend Aoi in the group, and despite Aoi's protests, Subaru decides to join the club. Shortly after, she gets a strange automobile-like staff and a magical transformation from the club's "president," the blobby creature from earlier, known as a Pleiadian. Aoi and the other members—Itsuki, Hikaru, and Nanako—have been looking for engine fragments of the spaceship that the Pleiadian used to travel in, so that it can go back to its home. But it seems that these girls are not the only ones searching for the fragments... [Written by MAL Rewrite]

An OVA bundled with the limited edition of the tankobon of the Kyou no Go no Ni manga. The staff and the cast of the OVA are the same as those of the Kyou no Go no Ni TV anime.

Sixteen years after its destruction by a meteor, Graviton City has been rebuilt into a futuristic metropolis. However, this is of little concern to superpowered high school student Eiko Magami, who only cares about her best friend Shiiko Kotobuki and arriving at school on time. Unfortunately, the incredibly intelligent Biko Daitokuji intends to befriend Shiiko, taking Eiko's place as the Shiiko's best friend using any means she can. Biko decides that, to accomplish this, she must defeat Eiko in combat. In order to overcome her super strength and speed, Biko creates a mecha and challenges Eiko in front of their school gate. As the two commence their battle, an extremely large spaceship hovers over Earth, searching for something left behind. [Written by MAL Rewrite]

In Iraq, a group of archaeologists discover ancient relics that prophecize the coming of a superior race and the end of all civilization. Meanwhile, back in Graviton City, as A-Ko and B-Ko's rivalry over Kei intensifies, Mr. Daitokuji sets up an arranged marriage between Miss Ayumi and Kei. Furious over the engagement, both A-Ko and B-Ko do whatever it takes to prevent the wedding from going through. Little do they know that another alien fleet is on its way towards Earth. (Source: ANN)