A masked creep kidnaps 9 people, puts them in a room, handcuffs them to a tube. He tells them their mission is to find out why there are there. Every ten minutes he will kill one of them unless they tell him the answer. The group is made up of a cop, two street thugs, a Vegas strip joint owner/mobster, a DA, a priest, a homosexual, a goody two shoes guy, and an Asian woman who doesn't speak English. What ensues is the typical American psycho horror: a bunch of people screaming at each other, insulting each other, grandstanding, deceiving, unable to work together, sometimes trying to work together. Obviously, they won't be able to find the answer in the first couple of 10-minute blocks. They touch on an important issue but don't see it's significance until later. Eventually they start "confessing" their sins, what each did that could have made someone mad enough to devise such a plan. So we learn something about them all. But whenever 10 minutes are up, the masked guy shows up, picks one of them, tells him the reason why they are there and then kills him. How it all turns out is quite interesting, but the ending not satisfying at all.
I'm not a fan of the idiots-bickering subgenre of horror, but this one does work. It doesn't take the insulting to insufferable extremes like the reality-footage movies but rather focuses more on the story. And you do want to find out what the story is. Even though the answer to the puzzle is somewhat mundane it is effective. The ending however is so weak it's puzzling. Performances are very good overall, and that's really the key in a movie like this. And the movie does manage to build quite a bit of tension.