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.
Cole Hauser
as Jack McAllister
Lena Headey
as Dr. Kathryn Jennings
Morris Chestnut
as Top Buchanan
Eddie Cibrian
as Tyler McAllister
Piper Perabo
as Charlie
Daniel Dae Kim
as Alex Kim
Kieran Darcy-Smith
as Strode
Rick Ravanello
as Briggs
Marcel Iureș
as Dr. Nicolai
Vlad Rădescu
as Dr. Bacovia
Simon Kunz
as Mike - Caver
David Kennedy
as Ian - Caver
