Disaster is looming in gangland because of a murder case. Cheung Sai-lun, Chinese American drama fanatic, returns to Hong Kong to look for opportunities in showbiz. Sai-lun somehow encounters a policewoman called Koo Yan-yee, who gives him an important assignment that requires him to pretend to be an orphan of Big Boss of Union Gang. With the assistance of a seasoned decoy called Ko Bun, Sai-lun becomes Big Boss. Sai-lun then repeatedly offers help to gang leader So Tsz-shan and an actress by the name of Chong Ming-lai. You Ching-shui, lady boss of some nightlife venue, and a trio of unrelated fresh-faced ladies also keep clinging to Sai-lun. While Sai-lun is starting to venture into gangland, he and Ko Bun become amicable partners. And with absolute protection provided by formidable fighter Luk Chau, crises are overcome. But nobody is aware of some shocking scheme has been awaiting him behind the gang activities.