In 1988, adventurer and filmmaker Andrew Wight was trapped in an underwater cave in Australia, along with 15 others. After the group's narrow escape, Wight approached his diving buddy James Cameron, the man behind Avatar, for help in making a film inspired by this ordeal.
In Sanctum, Papua New Guinea is home to the last unexplored region on the globe - an expansive underwater network of caves. Hard-nosed caver Frank McGuire (Richard Roxburgh) and his team are looking for a channel that leads to the ocean.
But things become difficult as an unexpected storm closes the mouth of the cave. The group of cavers - which includes Frank, his 17-year-old son Josh (Rhys Wakefield), billionaire adventurer Carl Hurley (Ioan Gruffudd) and his girlfriend Victoria (Alice Parkinson) - must find a way to survive, even as food and oxygen dwindle.
Sanctum uses the groundbreaking 3D photography system developed by executive producer Cameron's team on Avatar. The crew manages to get some spectacular close-ups of the divers in extreme conditions.
The film lacks depth at the start. But as it progresses, director Alister Grierson shows the darker side of humans - the one that emerges when people are pushed to the edge.
