He is contacted by an aging drug baron by the name of Chun Wei (played by Keye Luke) to help him uncover who is behind the murder of heroin dealers, in both Hong Kong and Amsterdam, from where Chun operates and manages one of the largest drug cartels. Wie wants to do all this ratting for a cushy price: he wants a US passport, one way ticket to New York’s Chinatown and not surprisingly, a whole lot of dollars. Quinlan is also re-hired by the DEA who want to make use of his knowledge as an ex-agent; the Department wants him to give information regarding the drug network in Hong Kong as well as Europe. He assists Chun Wei, as well as his former boss Odums (played by Bradford Dillman) and colleague Ridgeway (played by Richard Edgan), he is especially looking forward to show down the pretentious DEA honcho Riley Knight (played by Leslie Nielsen).
With information supplied by Chun, which Quinlan promptly passes onto the DEA, a noticeable number of cartels are actually busted and put out of business. However, rogue elements within the system pass on prior information about one such raid, and reacting to the tip off, the drug dealers ambush agents and policemen in a drug laboratory. When the agents conduct a raid, two agents are lost in combat - this makes Quinlan’s credibility questionable, and he realizes it would take a lot for him to regain their trust, and that most of them do not consider him to be anything but a nuisance. Chun Wei is also tracked down by the dealers, and meets a watery end in a bathtub.
Odums, who heads the US DEA in Hong Kong, tells Quinlan to come over, in order to find out who is responsible for the leaks; the ex agent flies down from London, and is attacked on numerous occasions by unknown assailants, and has miscellaneous violent encounters while in the City. After a number of red herrings and dead leads (quite literally, as the body count increases), Quinlan stumbles upon the word Juliana, the trail leads to the Venice of the North - aka Amsterdam. An eminent, hot shot political czar is vying for all the share of the drug trafficking. However the nameless person commits suicide before he can be apprehended by the law enforcing agencies.
One thing’s for certain, the DEA guys aren’t on his side, so Quinlan seeks help from a former dealer and close friend of his - Jimmy Wong (George Cheung). They soon discover the reason why the detection dogs are unable to sniff out drugs: the flower trade involves more than just ordinary flowers - the drugs are planted inside flower pots to avoid them being discovered. Quinlan and Jimmy singlehandedly, without help from local or US authorities, are able to bust a huge stash at a greenhouse in Amsterdam. The film was rumored to have its fight sequences chalked out and enacted by none other than Bruce Lee and Sammo Hung - the reality however, remains unknown. It is also rumored that Mitchum commented he did the film for money, and wasn’t really happy with neither the treatment of his character onscreen nor the treatment he received as Hollywood guy in Hong Kong.