Hero is a tale of assassins and a lone officer of the law, set hundreds of years ago in China. Jet Li plays the title role, Nameless, a local law official who has defeated several assassins bound to kill the King. He relates his tale in an audience with the King, with interesting consequences.
I can't really say anything else without giving the film away, but the plot is pretty good. What really shines about this film though is the visuals; It's definitely an art flick more than anything else. Colour is used very dramatically to convey a varying sense of reality, which is actually quite crucial to understanding what's happening. You may notice what I'm talking about towards the end.
The action is superb too, with scenes ranging from swordplay on water (a very Crouching Tiger scene) to an archery assault the likes of which you can't even imagine, it's definitely varied and interesting, though it does lean predominantly towards sword fighting. You do have to suspend a lot of disbelief because physics has been utterly sacrificed in the name of visual effect. Also largely done away with is continuity of motion between shots, also it seems in the name of making it look prettier and this felt quite jarring at times.
Overall I can't recommend this film enough - if you liked Crouching Tiger you'll definitely like Hero, and if you didn't then this might have enough frenetic action to keep you interested :-)