It is meant to be a horror, but I found it more to be a black comedy - in true Korean humour. A priest puts himself up for a medical experiment - in which he is needed a blood transfusion and is given vampire blood. We then follow his moral dilemma of devoting his life to God while wanting shag his friends wife silly.
It's a pretty schexy movie (the first Korean mainstream movie to show full frontal male nudity) and the cinematography is absolutely stunning. However, it is loooonng (2.5 hours) and a few scenes could have been left out of it - it's also one of those movies that I think you love it or you hate it (in the same vein as how people respond to Wes Anderson films) but I thought it was pretty awesome.