"Sanctum" is an intermittently exciting, but ultimately forgettable, action adventure movie that stakes a very strong claim on the title of "second-best trapped-in-a-cave movie of the last six months."

If you feel "127 Hours" would've been a better film if James Franco had had five or six other people down in the cave with him to bicker with, "Sanctum" is the movie for you.

Executive-produced by James Cameron, which presumably means he let them use his 3-D cameras, and he visited the set once or twice, "Sanctum" was directed by Alister Grierson and stars Richard Roxburgh, Ioan Gruffudd, Alice Parkinson, Dan Wyllie and Rhys Wakefield.

No, I've never heard of any of those people, either.

The film, based on a true story experienced by co-writer Andrew Wight, concerns a group of adventurers exploring an underwater cave in Papua New Guinea. When the cave is flooded, and they end up trapped, the explorers must find creative ways to get out to safety — and get along with each other in the process.

Roxburgh (the bad guy in "Moulin Rouge") is veteran cave explorer Frank; Wakefield is his estranged teenaged son, Josh. Gruffudd is a rich guy who bankrolled the dive, while Parkinson is his girlfriend.

Other than the father and son struggle and bonding, the plot doesn't have a whole lot going for it, mostly because the characters are so paper-thin.

It's also hard to take Wakefield seriously as the movie's hero because in some scenes, especially when underwater, he strongly resembles an androgynous glam rocker from the 1970s.

A lot of the scenes can be rather harrowing and horrifying; if you have any type of claustrophobia or fear of drowning, this is a movie you should probably avoid.

But "Sanctum" is also lacking in gravitas — it's another one of those movies in which people die frequently, but characters seem to have forgotten about the deaths two or three minutes later.

There's some truly dazzling 3-D work early on, especially during a helicopter ride in the movie's standout, pre-dive first act. (The movie was shot in Australia.) But once the characters are in the cave, the 3-D disappears for long periods of time, and is never all that impressive even when it does appear again.

The movie also does a pretty poor job of explaining the geography of the cave and where the characters are at any given time — we see a computer simulation of it, but that bears little to no relation to what we see later.

"Sanctum" has some things going for it, but ultimately you'll forget you even saw it by the next morning.

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Roll credits: "Sanctum"

Directed by: Alister Grierson

Starring: Richard Roxburgh, Ioan Gruffudd, Alice Parkinson, Dan Wyllie and Rhys Wakefield

Rated: R

Length: 1 hour 43 minutes

The Silver Screen rating: 2 stars (out of 5)

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