Photographed with the same image-acquisition technology James Cameron used on "Avatar," the movie on which we can blame most of the cruddy 3-D films since, the new suspense thriller "Sanctum," executive-produced by Cameron, presents images (underwater, generally) of pristine digital clarity, without the aggravating dimness of a movie shot in 2-D and then converted in postproduction. So it's the high-type 3-D.
The characters, the dialogue, the water-based peril — the stuff the 3-D is supposed to be supporting in the name of racking our nerves — well, "Sanctum" has problems with those. An Australian production, the film contains a tiny kernel of "based on a true story," that of a particularly rough underwater caving expedition undertaken by "Sanctum" producer and co-writer Andrew Wight, who's a rock star in his field and a pal of diving enthusiast Cameron. That risky, dangerous 1988 expedition claimed no casualties. Grimmer than "127 Hours," this movie is like a remake of "And Then There Were None" directed by Jacques Cousteau.
To make things odder, at heart it's a father-son bonding tale. The Ahab-like underwater cave diver Frank, played as a human growl by Richard Roxburgh, is leading his intrepid crew deep into "the largest unexplored cave system in the world" off New Guinea. A terrible storm gnashes its terrible teeth and communication with the rest of the team is cut off; the caves begin to flood, with the divers (including Frank's teenage son, played by the appealing Rhys Wakefield) unable to use their original point of entry to escape.