Master diver Frank McGuire is a leader diver comes a dangerous underwater cave with his son and his team. They feel interesting and surprise at the largest, most wonderful and least accessible cave system.
Mixed in with flat characters and tense action is an incredible 3D visual component - which is where Cameron's involvement in the project is most apparent.
Coupled with Frank's borderline sociopathic 'survival of the fittest' philosophy and his son Rhys Wakefield's bland sulkiness, there's not one likeable character to care about when things go wrong.
Stick that camera down an aquatic cave, wrap a paper-thin plot around it, slap the whole thing up on an IMAX screen and call it a movie. More truth in advertising: Call it a lame movie.
It's a continuing clash between laughably poor acting and ultra-serious brow-furrowing that renders Sanctum unintentionally hilarious, thereby deflating it completely.
