As a group of explorers are tracing a system of caves in the Papua New Guinea mountains, planning to map its path to the sea, a sudden flash flood and rock slide traps some of them. Knowing they’ve been given up for dead, they have no choice but to seek the flooded cave’s other end. The 3-D is actually a hindrance; except for the poorly written and awkwardly acted opening scenes, it’s blurry, murky and unnecessary (too many movies like this killed 3-D back in 1953). Aside from that, it’s a fairly decent little B-movie—brutal, often gruesome to a fault, but efficiently suspenseful. Richard Roxburgh leads the stranded party, with Rhys Wakefield as his resentful son and Ioan Gruffudd as his dilettante financier; everybody, including director Alister Grierson, does their middling best under the circumstances.