I saw this movie a few years back, I had to be around 6-8 years old so I can’t remember it well (only in bits and pieces). I must have seen it around 2002-2004.
I remember two couples going on a yacht (with an entertainment area on the lower level of the boat) in a foreign country. I believe Greece or Italy. They have an accident and one of the wives is either impaled or partially crushed under a portion of a boat from the accident on the lower level of the boat. One of the men (the main character) goes to shore to get help and either the other two stay behind to support the lady who is injured, or a least one of them goes with the main guy.
Next I remember the main guy sneaking around the city at night in the pouring rain, hiding under decks and in alley ways and such, avoiding the townspeople, because something strange happened to them, which made them hostile to him. At one point the main dude is hiding underneath a dock I think with a drunken older guy from the town who is somehow not effected by whatever the hell is going on.
Next I remember there is some kind of ritual going on. No more hiding as he has been discovered. In this tall, narrow, and round room. Everything is tinted blue from the lighting. They want him to give up and join them or something. His wife is there and either she was the leader behind this, or I think she was ‘turned’ or brainwashed too.
And that’s all I remember. lol