Decades after a rock church in communist Romania's Carpathians caved when
an expedition caused a landslide and buried everyone, Dr. Nicolai's
scientific team exploring the associated Templar Knights monster
fighting-legend discovers a deep, flooded cave system and hires the
brothers Jack and Tyler's brilliant divers team to explore it. Another
explosion traps them, after finding a mysterious parasite turning all
species carnivore, and later an independently evolved predator species.
Jack may be infected and turning, but Tyler sticks with him, so the group
splits, hunted by the monsters, which also fly.
A group of cave-divers and scientists explore a newly found cave system in
Romania. However, rockfall blocks the exit and after delving further into
the cave, the group discover a pack of deadly creatures are waiting for
them. With their leader Jack having very strange side-effects and with
their numbers dropping, the group must delve even further into the cave,
battle the creatures and hope for an exit.
Thirty years ago, in the Carpathians Mountains of Romania, a group of
explorers blows an entrance to a cave hidden under a church, but the
explosion causes a landslide and they become trapped inside. In the present
days, the expedition leaded by Dr. Nicolai and his assistant, Dr. Kathryn
are exploring the place and they find the access through an underwater
river, requesting the experienced cave divers team leaded by Jack. Dr.
Nicolai discovers that, in accordance with the local legend, the church was
built to seal the cave as a display of God's protective power, and that
Templar Knights entered the cave to fight winged demons. When the group
reaches a cave though a tunnel one mile below and three miles in, a
creature attacks one of the members and his breathing apparatus explodes,
collapsing the tunnel and trapping the group in the cave. Soon they realize
that they are the rescue team and they have to find an exit to survive from
the attack of the monsters.