An old saying that we just made up goes like this: make a movie about a topic that no one has really addressed and your film automatically becomes an interesting novelty simply by existing. It's why "Dodgeball: A True Underdog Story" will forever be considered the definitive dodgeball movie, but "Kansas City Bomber" is not the definitive roller derby movie considering "Whip It" came a couple of decades later, despite that film being inferior to "Kansas City Bomber." Of course, we can't find a whole lot of super realistic cave-diving movies, so congratulations, "Sanctum," you're a cinematic footnote by default.
"Sanctum" begins at the Esa-Ala Caves in the South Pacific, where a team of Australian daredevils are on a well-funded mission to find the very bottom of the world's longest cave. Seems as if there are underground tunnels connecting the caves to the sea, and the only issue is navigating waters that have never been explored by human eyes. Based on a true story, "Sanctum" follows a group of explorers who find themselves trapped underground after a violent tropical storm floods the caves. They are forced to swim their way out, so an exploratory mission becomes a struggle to survive, as cave-diving is a very specific skill-set, and not everyone present possesses said skill set.
One of the more capable fellows is young Josh (Rhys Wakefield), a pretty blond sprite with a rebellious streak who resents being dragged underground by his father's cold, clinical ambition. The ornery father Frank is played by a surprisingly grizzled Richard Roxburgh, a thespian with a dandy streak who has apparently reinvented himself with a splash of Stellan Skarsgård and a smidgen of Dolph Lundgren. Frank is a salty type, fed up with an apparently disappointing son and a lack of funding that has turned his job into more of a chore than a genuine passion.
The film rides on the predictable patterns of the father-son conflict, but it's a more interesting dynamic given that Frank is so singleminded that he lacks the patience for drama or tragedy. It's his almost socially-retarded tunnel vision that provides the motor for the trapped survivors, which is a boon in regards to their potential survival. But it's contrasted with a sociopath's contempt for sentimentality that causes him to sneer at superficial conflict, to attack when confronted by ignorance. When a tactical mistake causes the death of another traveler, Frank doesn't deny that he may have had a hand in decelerating the victim's life expectancy. At some points, you're wondering if this cynical young man and his heartless father might hug. At others, you're waiting for him to murder one of the others in their group.
There's not much else to "Sanctum," which, if you remove the father-son story, is the definition of how 3D threatens to change the art form. The camera moves around crevices, under water, and through death-defying angles to place the audience in the middle of this suspenseful situation, the artificial thrill resembling a theme park attraction. Despite the violence and language, "Sanctum" has the depth of character and narrative momentum of an early '90s Disney movie, with characters barking belabored one-liners at each other and laughing cheerfully as if there was something artificial (or in Disney's case, animatronic) about the entire scenario. The sweeping vistas captured by the camerawork combined with the 3D only adds to this unreality. You wonder if the real life people who died in this tragedy really used their last words to utter bumper sticker platitudes.
The mission is being controlled by a loaded American, played by an exceedingly phony Ioan Gruffudd. A few years ago, Gruffudd was the lead in a couple "Fantastic Four" tentpoles. It's "Sanctum" that reminds us why this once-leading man is now auditioning for the Hallmark Channel. Starting off as a globetrotting snob, businessman and amateur thrillseeker, Carl reveals himself to be extremely ill-equipped to withstand a situation where saving his own hide isn't priority number one. As a result, Gruffudd goes from different extremes of high camp, first as a conceited braggart, and then a mewling coward, before landing on default villain. It's not a particularly convincing arc on paper, and Gruffudd doesn't exactly do his part with his broad line readings, though he does get a peculiarly overwrought, "Have you no decency?" to chew into.
Most of the claustrophobic "Sanctum" will appeal only to those who like getting strapped in and are ready for exploring. The immersive 3D and claustrophobic locations add to a certain gravity where the only real reaction from an audience member could be, "Yep, that looks like a cave alright." When you've got a cave and 3D water and a few forgettable character tropes, the possibility for imagination remains faint. Considering "Sanctum" is the result of whatever pennies were found underneath executive producer James Cameron's couch, you'd expect a little more. [C-]