Our protagonist Hinokami Chie transfers to Tsukumori Gakuen due to her parents' work. There she meets a black cat with two tails, and that's when strange things start to happen; including the introduction of another transfer student.

Chie learns she is the owner of the 'Hitofuta no Sho' - a legendary scroll. With the cat's guidance, she must face the responsibility of sealing a mysterious dark force gone astray...

[Edited from Yamiyoru's Livejournal]