The series is set in the mou-lam in early 20th-century China. A grey-haired Wah Ying-hung travels alone to an island to settle an old feud between the Wah and Chek families. He has been separated from his family for over 20 years after they were ambushed by enemies while sailing back to China from America. Wah's wife, Kit-yu, was killed by the attackers; their daughter, Mun-ying, was thrown overboard and presumed dead; their son, Kim-hung, was raised by Wah's servant Sang-no. Kim-hung becomes bitter enemies with Sze-to Mok-mun after the latter killed Sang-no. He also encounters Tap-suet by chance, falls in love with her, and marries her. However, they incur the jealousy of Si-ngo, the daughter of the Wah family's servant Kwai-buk, because she has a crush on Kim-hung. In the meantime, Wah Ying-hung resolves the feud and becomes an ally of Chek Lin Ying-wong, the Chek family patriarch. He also accepts Chek's son, Chek Ngan, as his apprentice. He also develops a crush on Tze-yi, one of the Chek family's mercenaries, because she resembles Kit-yu in appearance. Mun-ying had actually survived and was renamed "Ging-tin". She was raised by Yuen-lo-wong of the HellSect and groomed to become the sect's leader. She developed a cruel and treacherous personality under Yuen-lo-wong's influence and eventually murdered her foster father to secure her position in the Hell Sect. She pretends to love Mok-mun and manipulates him to help her. With support from Mok-mun and the Japanese Iga Sect's ninjas, Ging-tin leads the Hell Sect to attack other martial arts sects in her ambition to dominate the mou-lam. She also incites conflict between Sze-to Mou-leung and the Iga Sect, after discovering that Mok-mun is actually the biological son of the Iga Sect's leader. Wah Ying-hung and his son combine forces with the Chek family and other sects to resist the Hell Sect and its allies. Wah restores peace in the mou-lam after defeating and reluctantly killing his evil daughter.
Cast
Kenny Ho as Wah Ying-hung, the protagonist of the series. The titular "Blood Sword" refers to his weapon, a red-bladed sword.
Law Chung-wah as Wah Kim-hung, Wah Ying-hung's son.
Veronica Yip as Tze-yi, a mercenary hired by the Chek family. She is similar in appearance to Kit-yu, Wah Ying-hung's deceased wife.
Yeung Chak-lam as Chek Lin Ying-wong, the patriarch of the Chek family.
Esther Kwan as Ging-tin / Wah Mun-ying, Wah Ying-hung's lost-long daughter who becomes the evil leader of the Hell Sect.
