Gred（任达华饰）是个一生致力于研发一种可以挽救绝症病人并可使人变成超人的新药的医生，他在他国外老师的支持下展开研究，在研究取得突破的时候，他的教授意图窃取他的研究成果，在争斗中教授病发身亡，而因为教授的死，Gred的研究没人支持而被迫停止，他带着他的学生兼女友回到香港。在香港，他的研究得到了旧同学现任医学委员会委员周正春（Mike）（郑浩南饰）的支持。就在一切进入佳境的时候，Gred的女友被Mike迷奸了，当然这些女友也没有和Gred说起，之后由于Gred长期忙于研究工作，女友耐不住寂寞，在Mike的强逼下，半推半就和他又一次发生了关系，而这一次被Gred碰到了，可是因为体位关系，女友看到了而Mike没有看到Gred（看到男友抓奸在床，仍处变不惊，继续战斗到Mike瘫软）。事后女友和Gred决定报复，方法就是让Mike成为新药的实验品。实验刚开始时，Mike体能大幅增强，但很快就因受到药毒的侵蚀而挂掉了。因为开始了人体试验，所以新药有了大的突破。在以后的日子里，Gred碰到绝症病人就给他们使用新药，开始的时候病人很快康复了，可是后来，副作用显现了，病人身体出现大规模的溃烂，纷纷死亡，Gred悔不当初，服下新药自杀而亡。

In England, Dr. Greg Fong invents a super steroid (SS160) which can cure virtually all illnesses and disorders (including impotence and idiocy) and generally makes someone superhuman. But his obsession with the super drug, begins making him mentally unbalanced. After the death of his co-worker, Fong returns to Hong Kong with his new wonder drug and begins working with old friend Dr. Mike Chow (Mark Cheng) Mike (who sells black market kidneys) then drugs and rapes his Fong's girlfriend Vivian who falls for him in return (!). Fong takes the affair as good reason to do a bit of human medical tests, and begins doing secret medical experiments on Dr. Chow, as well as a host of other patients, notably including policeman Chan Sum who begins turning superhuman.