Master diver Frank McGuire has explored the South Pacific's deep underground Esa-ala Caves for months. But when his exit is cut off in a flash flood during a hurricane, Frank's team—including his 17-year-old son Josh and financier Carl Hurley—are forced to radically alter plans. With dwindling supplies, the crew must navigate an underwater labyrinth to make it out. The unavoidable question: Can they survive?

Bonus Content:

 

• 4K Presentation from the Original Elements
• Presented in Dolby Vision
• Audio Commentary by Emily Higgins and Billy Dunham
• Audio Commentary with Director Alister Grierson, Actor Rhys Waskefield and Co-Writer/Producer Andrew Wight
• Deleted Scenes
• Sanctum: The Real Story
• Nullarbor Dreaming