The title tells you all you need to know – set at the highest levels of imperial China, Sex and the Emperor is full of palace intrigue and lots – lots – of sex. (And a bit of torture.)
It's told through the eyes of Li, a servant who isn't quite the eunuch he's meant to be. Nonetheless, he does the emperor's bidding – whether helping him perv over women, rescue his favourite concubine from a whorehouse or deal with his enemies.
A full-on Category III shag-a-thon (with a bit of torture), Sex and the Emperor might be best avoided if you're not broad-minded; a perfect example of Hong Kong cinema at its absolute wildest.