let me try to summarize what the On Demand summary said.
in 1957 (or so) communist russia successfully invades america. the last bastion of resistance and freedom is the fortress city of Las Vegas. the rebellion is ruled by The King, of course (elvis, i'm assuming) but he dies or something so sword-wielding guitar players from all around are battling their way to Las Vegas to become the new king. so the main character (i think his name is Buddy) has to fight bounty hunters, rival "samurai" and even Death, himself to become the new King.
the fight scenes are actually well done. i think they sacrificed acting talent to get people who can actually sort of fight with swords/martial arts etc.
anyway, it is freaking awesome.