《《遗传学歌剧》》A rich lord loves a girl. A maid who has seen the two accosts the lord in a park and embraces him. This is seen by the girl who calls off their relationship. The lord decides to commit suicide, but the butler replaces the poison with water. The girl, her love now restored, rushes to what she thinks is the lord's deathbed.富家子弟周通(许冠杰 饰)武功高强到处仗势凌人其妹妹周吉(吴君如 饰)也十分无理取闹他们的母亲太君(许冠英 饰)一直想他们定性并能够成家立室可是在周吉的新婚之夜夫君林嘉声(黄百鸣 饰)忍受不了周吉而逃走了自此太君便茶饭不思周通于是为母亲办寿筵冲喜更想请 著名魔术师大围高栢飞(张国荣 饰)助兴与此同时白雪仙(关之琳 饰)乔装出来逛花市与高栢飞一见钟情白父(吴孟达 饰)得知事情后以为女儿已怀孕便找到高柏飞提亲却误以为周通就是高栢飞… 讲述两个男人为了抓住连环杀人犯而违反法律和原则的故事“谁是怪物是你是我还是我们”...