Hong Kong's Ironman stepped up to the plate when Dr. No (1962) took the world by storm in the 1960s. Tso Tat-wah, the quintessential tough guy of Cantonese cinema who had appeared in dozens of popular action films, was licensed to spy in several 007 imitations. Here, he is Agent 303, the lucky number "3" a vivid sign of East-West integration. Presented in glorious widescreen, the film is garnished with secret weapons and ominous hideouts, mind games and technological intrigues, violence and sex, the latter in the form of a silhouette striptease!

A mad scientist wants to get his hands on a certain growth-accelerating serum developed by Hong Kong scientist Dr. Li Zong-Hua so that he can create an army of supermen and conquer the world.

Cheng Chung-bo and his family become the target of attack and abduction orchestrated by a crime syndicate coveting the treasure map in his possession. His youngest son Fai is hauled to safety by the space station scientist and gains great power as the Moonlight Spaceman under his tutelage. Fai returns after six years with the mission to crack down on the ring. Flying Heroine Ma Chau-wan is sent as his backup by the understandably worried scientist. The spaceman approaches neighbour Ho Kei-ming's daughter Yuk-wah in order to probe into the father's dealings with the crime ring. Ma, meanwhile, charms her way into Detective Wong's investigation squad. Fai and the detective make a narrow escape from death but are dealt another setback, with Fai's mother and Yuk-wah abducted. (Continued in 'The Female King Kong')

The crime syndicate demands that Cheng Chung-bo lead the way to the treasure trove, holding his family hostage. Booby-trapped, Cheng Fai disengages the device and flees to join Flying Heroine Ma Chau-wan and Detective Wong. Meanwhile, the ingenious scientist Dr Ng is enlisted by the ringleader Ho Kei-ming to match wits and brawn with Fai and Ma. Ma slyly earns the trust of a bewitched Ng, claiming to be Fai's biggest foe. Ng ushers Ma into the headquarters where he meets his doom. With his patience running out, Ho grasps an apprehended Chung-bo on a treasure hunt while the pursuers are diverted from their course. Ma recognises her long-lost father from among the gangsters and brings him to his senses with words of absolution. The father pledges his alliance to the duo in crushing the gang and saving Chung-bo and wife.