Ignore the marketing decision to use executive producer James Cameron's name to sell tickets, and the promise of the 3D process to deliver spectacle (while boosting admission prices). What remains is an amateurish action-adventure film that first-time feature screenwriters John Gavin and Andrew Wight and sophomore director Alister Grierson ("Kokoda") sent spiraling deep into the abyss.
Despite the "inspired by a true story" tag, the narrative retains only the most basic incident of Wight's real-life Pannikin Plains cave-diving expedition of 1988: A flash flood traps a team in a large subterranean chamber of a vast underwater cave system. The near-disaster that actually occurred in Australia becomes an unbelievable underwater drama set in the world's largest unexplored cave system, Esa Ala, situated in Papua New Guinea.
Master diver Frank (Richard Roxburgh of "Van Helsing" and "Moulin Rouge!") is the gruff, no-nonsense expedition leader who can feel the cave but seemingly has few feelings for human beings. The cave exploration provides the long-absent father opportunities to yell at his resentful teenage son, Josh (Rhys Wakefield of "Broken Hill"). He also gets to demean adrenalin-junkie financier Carl (Ioan Gruffudd of "Rise of the Silver Surfer") and dismiss the two females (Alice Parkinson and Allison Cratchley) as panic-stricken liabilities. The cave system emerges as the fatal attraction.
Roxburgh deserves praise for his performance, the only credible one in the entire film. Even when repeatedly saddled with reciting the same lines from Coleridge's "Kubla Khan," the Australian actor lends an air of reverence to the poetry of a sacred river running through "caverns measureless to man down to a sunless sea." Frank may have ice water running through his veins, but he's the only person capable of guiding the group through the labyrinth with dwindling supplies and no contact with those above ground. Roxburgh looks and acts the part.
The other cast members elicit laughter for all the wrong reasons, although Wakefield's acting improves as the movie wears on. Flat characters spewing inane dialogue don't have a chance, particularly when the 3D camera captures their wooden performances in close-up. The over-the-top Gruffudd is better hidden behind a diving mask.
Grierson's direction hinders the visual look, since his choice of close-ups, medium shots and a moving camera don't make for good 3D images. Although a few extreme long shots present the natural landscape in breathtaking deep-focus views, most of the movie takes place in inky waters or brown-walled caves -- not the best subject for 3D technology.
"Sanctum" is nothing sacred, and perhaps the worst film of the new year to surface in the darkness of the theater.