Adventure-loving couple Eric and Jennifer convince their friends, Yolanda and Viktor, to explore a remote, uncharted cave system in the forests of Northern Australia. With a tropical storm approaching, they abseil into the mouth of the cave, knowing they'll be safe underground. But when the caves start to flood, tensions rise as oxygen levels fall and the group find themselves lost, disoriented, and trapped. Little do they know, the dank air and rising water are the least of their worries. They discover the storm has brought in a pack of apex predators -- dangerous and hungry crocodiles. As danger mounts, long-kept secrets emerge and the friends turn on each other in a frantic fight for survival.