A group of about forty people 'wake up' standing in a large circle without any awareness of how they got there. Each person stands on an illuminated spot. Once every ninety seconds or so, a pulsing column rises from the centre of the circle and shoots out a beam that kills one of the people. Through a process of fatal deduction, they work out that they have the collective power to vote for who gets killed next.
Basically, it's like a version of Fifteen-To-One where Sandi Toksvig murders the contestants.
(Note to self: Find out who to pitch gameshow ideas to on Sky/Channel 5)
Anyway, the whole group of people waking up in a strange place and working out why they're there thing has been done many times now. Best of which (in my humble) is the first Cube film, however this one ain't bad, if it sounds like your sorta thing, you'll probably enjoy it.