Overheard is an enjoyable yet not more much than that cop drama involving three HK police investigating stock market irregularities involving a company. As the police (played by Lau Ching-Wan, Daniel Wu, Louis Koo) listen in on what is happening in the company they overhear some stock market manipulation being planned and can't resist the temptation to make a few (or a lot) HK$ themselves.
Of course the police all have their individual stories which maybe explain why they are morally conflicted but basically good including Louis Koo who is dying and has a sick son so wants the money for them. Of course once they have entered the wrong side of the law they can't get out but no sooner have they managed to avert the anti-corruption investigation by the police then the bad guy behind the company (played by Michael Wong - and boy is he bad) is after them too.
Its a nice movie, it has a strong cast and some twists to savour and is generally produced well. Of course being a modern HK movie it has to steer within the boundaries set by the Chinese censors. Thus you know they will not get away with it but the ending and resolution of the film does manage some genuine surprises even if the plot stretches credibility somewhat in doing so. A win but not a knockout, but a win all the same.