In an Eastern-styled fantasy setting, a brother and sister team of sacred guardians is beset by the Xuan Gui Zong, minions of Miè Tian Hai, who seeks the Tian Xing Jiàn sword that they possess. Hai's appearance leads to the defeat of the brother, but his sister, Dan Fei, jumps off a cliff to temporary safety. Later, a wandering swordsman comes across a ruined temple, where a statue of Buddha is protected by an umbrella against the rain. When he takes the umbrella for himself, a man resting under a tree nearby informs him that he must be compassionate to the next traveler he meets as a trade-off for taking the umbrella. That next traveler is Dan Fei, still being pursued by the Xuan Gui Zong minions. Both his promise and the enemy's sorcery leaves the wanderer unable to avoid getting involved.
(Source: Anime News Network)
— Description from AniList community (anilist.co).
