Private investigator AU YEUNG YAT gets acquainted with a woman in a casino. He is later alleged of murder when the woman falls down her house and dies.

After investigation, YAT discovers that it is all his father SUN's plot. SUN hopes that YAT will succeed his business, but YAT refuses.

Business brothers TUNG YAT-FUNG and YI-FUNG arrive in Shanghai. SUN is emotionally stirred when he sees YAT-FUNG.

SUN's man CHAN HUNG kills Gang leader TIN PUI's subordinate. SUN promises to handle TIN PUI for CHAN.