The series begins in 12th century Japan and centers on Kuro, a character based loosely on the legendary Japanese swordsman Minamoto no Yoshitsune.

Kuro, a 12th-century man, flees into the mountains after losing to his brother, where he meets a strange, beautiful woman named Kuromitsu. Kuro falls in love with Kuromitsu but realizes she conceals a dark secret. She is unable to die and continues to live for thousands of years as Japan evolves into a future society.—Morgan VanGogh