After a group of biologists discovers a huge network of unexplored caves in Romania and, believing it to be an undisturbed eco-system that has produced a new species, they hire…

Group of Spanish friends on the tropical island holiday of a lifetime. Discovering a secret cave adds adventure. They enthusiastically go underground with their camera, but soon become hopelessly lost….

A group of former military elites set out to explore an uncharted abyss, not knowing their worst nightmare is waiting for them deep beneath the ground.