If there's more than an echo of Bruce Lee here, with Yen adopting a secret identity that's clearly inspired by Lee's Kato character from The Green Hornet, and there's also a sign referencing the Chinese as being the "sick men of Asia". The latter is no surprise, since the character of Chen Zhen was originally created by Lee for Fist of Fury, which had a similar sign. Mind you, Chen was also played by Jet Li in the confusingly similarly-named Fist of Legend, and it's not quite clear how the chronology of these three fit together. Best not worry and just concentrate on this one, which starts with Chen helping the French in World War I. When that ends, he takes the identity of a dead colleague, and returns to Shanghai, where he joins the resistance against the ever-increasing influence of the Japanese. He gets a job managing the Casablanca nightclub (the Marseillaise scene is also lifted), owned by Liu Yutian (Wong), and begins a relationship with Kiki (Shu), a singer there who, unknown to Chen, is also a Japanese spy.
As the political chess game continues, things escalate after a Japanese "death list" of pro-Chinese agitators is leaked. Chen, in his alter ego, tries to protect those on it, but most end up dead or in hiding. Kiki's position becomes ever more tenuous, and the Japanese net closes around Chen, in particular after he kills the brother of Colonel Chikaraishi (Ryu). The Colonel's anger is kinda understandable, since Chen previously was also responsible for killing Chikaraishi's father in a dojo duel. You won't be surprised that this all ends in Chen facing first the entire male population of Japan, or thereabouts, then a one-on-one duel with the Colonel. Albeit not in a library, or involving a candlestick. Yen's choreography is as slick and fast as a well-greased otter, yet what lurks between the fights has a nasty xenophobia, that doesn't just extend to Japan, but any other foreigners depicted here. While Wong and Shu deliver solid enough performances, you never care for the hero, and there isn't enough heart or intelligence to make this much more than an extended highlight-reel of robust martial arts.