Hagun Seisenki

Year 1691/2:
The land ruled by the Satomi clan Inue Shimbē Masashi and his twin younger sister, Fuse, had lost their parents—thus becoming the new clan heads. Inue becomes the leader of the Satomi Hakkenshi (or more simply Hakkenshi) as well, 8 elite warriors, loyal to the Satomi's clan.

Fuse believes yokai are people as well to the much to her brother’s dismay. After a trip to the woods she is rescued by a yokai, Yatsufusa, who she falls in love with. Tamazusa who witnessed Fuse’s confession grew with jealousy and cast a curse upon the two, a curse of tragedy.

Year 1991/2:
The Hakkenshi have reincarnated into people all of which are studying or working at CLAMP School. Inue has been reincarnated into a boy named Kazae Tōma. Yatsufusa to a new math teacher named Shirō Fuyukaze. Tamazusa into a younger kindergarten girl named Azuya Nagisa.

A battle begins and Kazae’s life is in danger for he cannot remember his past life save for some dreams. It’s up to the Hakkenshi reincarnations to protect him as a quest to break this curse continues on in this new generation.