The Sword from the Sea

The story revolves around a quest for a powerful sword hidden underwater and guarded by a sea monster. Lau Hark Suen's character sends his acolyte to find and retrieve the sword. Along the way, she meets Cheung Ying Tsoi and two fish-selling siblings. The brother, Kam Hoi, is temporarily endowed with kung fu powers by an old crone who wants him to bring back her son and daughter. The sister is cast under a spell by Sek Kin, given a new identity and becomes his tool to obtain the sword.
(Source:
HKMDB by dleedlee)