After MASTER SIU has finished the 'TEARFUL SWORD', he holds a premonition that his own son will be killed by this superb sword. To save his son from the ill fate, he sends him to live with his friend, SZE-MA, whilst he resides in a quiet place carrying the sword with him. Years later, the TEARFUL SWORD is stolen by a girl, SHIU. Fearing that the sword may hurt his son, MASTER SIU thus sends his student KO to protect KWAN, MASTER SIU's son, who grows up to be a kung-fu master and also the chairman of the SZE-MA SECURITY ORGANISATION. KWAN is controlled by an ambitious counsellor, LOI, who plot to posses LION HALL, another prestigious security organisation run by CHU. KO secretly follows SHIU to LION HALL where he meets CHU. KO and CHU, both appreciate the other's heroic mettle and become good friends.

LOI sends MAO to go under cover in LION HALL but she later falls in love with CHU. Meanwhile KO dates a challenge with KWAN and during the fight, KO's sword is broken by KWAN's precious sword. At that moment, SHIU gives the TEARFUL SWORD to KO. Fearing that the TEARFUL SWORD may hurt KWAN, KO runs away at once. Seeing LOI has tried all the dirty means to ruin LION HALL, KO decides to give CHU a hand to strike against LOI.