Ken (Roger Kwok), has mastered mahjong and is nicknamed "The Half-Century Man" because he once won 50 hands of mahjong in a roll. Everybody expects him to succeed his father, Uncle Man (Ha Yu), to be the Grandmaster of Kungfu Mahjong. However, Uncle Man has a heart attack on his 60th birthday and is hospitalized. Sophie, Uncle Man's new wife takes the opportunity to persuade him to leave his estate to her instead of his son. Uncle Man tells her that she would get her wish if she beats Ken in a game of mahjong.
Meanwhile, Ken falls in love with Nancy (Shirley Yeung), a lady of rotten luck. All her previous boyfriends were either bankrupt or had died in accidents. Ken's fortunes go downhill instantly, to the extent that when he plays mahjong with Sophie and her lover, Bowie, he's almost cleaned out.
Ken was told by his father to seek help from his old friend Grand Slam Ben (Nat Chan). Ken followed Bens instructions and re-built his confidence in mahjong playing. To make sure that they would succeed Uncle Man, Sophie and Bowie kidnapped Nancy and her sister. Should Ken win the final duel, they would be harmed. On the verge of admitting defeat, Auntie Toni (Yuen Qiu) arrived with Nancy and her sister, having saved them from Sophies men. Ken, after wooing the tiles, miraculously won 50 hands in a roll and finally succeeded his father as the new Grandmaster of Kungfu Mahjong.