Five people wake up in a room. There’s door/panels in the centre of each of four walls as well as the ceiling and the floor. Each hatch leads to another identical room. Sometimes the rooms are booby trapped. Sometimes there not.

Nobody knows each other or knows how they got into the room. The group slowly starts moving from room to room using a boot to test for traps. Which works for awhile.

First time director Vincenzo Natali managed to get financing for this low budget horror by creating a short film first called Elevated. Natali uses the set as best he can to create tension and terror. The group slowly start to bicker. How did they get in the room. Does someone among them know more than they are letting on and what do the numbers on each room mean?

This is a pretty fun little thriller. It managed to spawn a sequel and a prequel although neither matched the original. Natali would move on to even creepier horror movies.