A priest with a haunted past and a novice on the threshold of her final vows are sent by the Vatican to investigate the death of a young nun in Romania and confront a malevolent force in the form of a demonic nun.
Best friends Marie and Alexia decide to spend a quiet weekend at Alexia's parents' secluded farmhouse. But on the night of their arrival, the girls' idyllic getaway turns into an endless night of horror.
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 the best American team of underwater cave explorers in the world. While exploring deeper into the underwater caves, a rockslide blocks their exit, and they soon discover a larger carnivorous creature has added them to its food chain.
