When Mo Dong Hero # 7 Mok Sing Guk discovered his apprentice nephew Sung Ching Sheu attempting to rape new Ngor Mei Sect leader Chow Chi Yerk, Mok was understandably incensed. In a righteous rage, Mok tried to kill Sung, but failed and let Sung briefly get away from him. Mok finally did catch up to him, but became entrapped by the Beggar's Union Elder Chan Yau Leung, who compelled Sung to murder Mok.
How was it so difficult for Mok Sing Guk to try to kill Sung Ching Sheu? Mok was one of the Mo Dong 7 Heroes, and although he was the youngest and weakest of the seven, he was good enough to even give such excellent fighters as White-Browed Eagle King Yan Teen Sing a run for his money. A junior fighter like Sung Ching Sheu, whose Mo Dong Sect martial arts would have been *very* familiar to Mok, should not have been difficult for Mok to kill. Logically, Mok should have been able to kill Sung with one blow in the very room where Sung had tried to rape Chow Chi Yerk, not let Sung evade him all the way into the wilderness where he would be entrapped by Chan.