Every nightmare has a beginning. In this prequel to the cult hit Cube, one of the most successful sci-fi thrillers of the last decade, a new group of unwilling participants frantically moves through an ominous construct of cube-shaped rooms. Each room holds the threat of hideously inventive and painful death. Finding the real exit, however, may not offer the freedom one seeks.

Following the grisly 1997 Cube and its 2002 sequel, Cube 2: Hypercube, Cube Zero stretches the original's The Twilight Zone-like, strangers-in-a-box theme a little thin. Fortunately, there's a difference this time. The hero is not just another disoriented captive of the Cube's interconnected--often lethal--rooms, but rather a geek named Eric (Zachary Bennett) who sits in a control station wrestling with his conscience about inflicting misery on innocent people. Taking orders over the phone from some almighty, unknown power in a distant office, Eric reaches a breaking point and enters the maze himself, intent on helping a woman (Stephanie Moore) who doubts his motives. The existential bent of the prior films becomes even more Kafkaesque this time with the arrival of a white-collar team of tormentors, bureaucratic tyrants who can't or won't explain the point of the Cube. Imaginative writer-director Ernie Barbarash rescues what might have been a tedious formula flick. --Tom Keogh