In the heart of a primitive jungle with few human traces in a place in Papua New Guinea, there is a huge cave called Issa Ala, the mother of caves. The wealthy explorer Carl (Ioan Gruffudd) spent a lot of money to hire Frank (Richard Roxburgh) and his team with rich cave exploration experience to explore here. In a blink of an eye, a few months have passed. Although Issa Ala's exploration has been quite effective, the progress is still slow. At the same time, a strong tropical storm is about to come, and cave exploration is imminent. Carl quarreled with Frank for this, and the latter went all out and dived into the water with his already exhausted partner Jude (Allison Cratchley) to challenge the dangerous passage known as the "Devil's Limit". On the other hand, Carl's girlfriend Victoria and Frank's son Josh also went to explore the cave. Little did they know that a catastrophe was approaching... This film is adapted from Andrew Wight's real experience of caving in Western Australia and was shot with the 3D camera of "Avatar".