Pitch Black was never meant to be a trilogy, but the success of the film spurred on a franchise of stories, including a cartoon sequel which took place immediately after the film, and a less direct sequel which took place back in civilization.
The only thing tying these films together however was a few characters. The first film was a monster thriller - with some elements of a startle flick - the cartoon was a heroic adventure piece, and the film sequel was a political action adventure.
Moviehole recently reported that a third film, as yet unnamed, has begun casting, which will be a return to the thriller roots of the series.
Riddick will once again be stranded on an alien planet and forced to fight for his life against incredible odds.
There should be links to the "politicalish" adventure of the second film, but it will mostly focus on tying up Riddick’s character while he fights aliens, and apparently a force of mercenaries who have been sent to make sure the monsters get the job done.
The flash-backs in the film will show us Riddick at the height of his power, as Lord Marshal Riddick. The events which brought him to this new alien world will unfold in flashbacks throughout the film.
There will also be some connection to the characters of the first film, as one of the characters in the casting call has the same surname as the commander of the ship in which Riddick crashed-landed on an alien planet in the first film.
I’m guessing Vin Diesel will play Riddick again. I can’t imagine what else he’s doing with his time these days, and we’ll likely see a couple faces we recognize in flashbacks, but it’s mostly an all new cast. David Twohy - the director of the second film - is directing the picture, which doesn’t yet have a release date.