nanoki

Kagome Higurashi, a normal 15-year-old girl, falls down a dry well--and finds herself in the feudal past, 50 years after her ancestress Kikyo imprisoned the half-human/half-demon Inu-Yasha. As the reincarnation of Kikyo, Kagome possesses a magic jewel that greatly increases the power of demons.

In the beginning of the 21st century, a world war breaks out over interplanetary travel tech. The environment is pretty much destroyed so mankind leaves Earth and starts Star Calendar 00.