After an opening couple of scenes that set up a police versus street gang scenario there is a car crash. This crash leads to an assassin (Daniel Wu) being hired to come to Hong Kong to do a hit. The assassin, however, is set up by a greedy crook who gets caught and strikes a deal with the cops. The cops follow every lead but the assassin is too smart. He has also hooked up with a local prostitute (Cecilia Cheung) [with a heart of gold] who escorts him around the densely populated area known as Mongkok.
The assassin knows what he has to do but - it turns out - he's an okay guy. He's actually more interested in finding his girlfriend - who unbeknownst to him - has been in a terrible car crash that opens the film.
The cops, in turn, are not all good guys. They sometimes play dirty and have shady methods. One (Alex Fong Chung-Sun) is tired of his job but he knows how to play the opportunist game; at one point he sets up a cop murder to look like an accident. Another (Anson Leung) is an new cop who is quick on the draw and would rather shoot first and ask questions later. But he's such an innocent looking guy you can't fault him.
In fact, pretty much everybody is okay. And, or course, the assassin and the cops are basically one in the same. It's just a matter of time before their paths cross.
One Nite in Mongkok has a high production value, is well paced and has a lot of quality actors. But it is also manages to be uniquely convoluted and predictable. It's as if director Derek Lee - in trying to fashion something new out of a formula - decided to throw a bunch of wrinkles into the mix with the hope that by the end everything will have more power and meaning. Some of those interesting wrinkles include taking the overall story of a bunch of cops chasing a bunch of crooks and narrowing it down to being just about three or four characters, giving us a mainland versus city theme and making the assassin so nice it turns out he is doing his first and last job.
Lucky for him. Or maybe not....
While the film does become more engaging as the subplots develop it still treads ground that has been tread often and much better. It does have a dark gritty side, which is welcome. But the production value actually undermines this a bit. Despite all of this the film garnered 12 Hong Kong nominations. It won for Best Screenplay and Best Director.