The Caveis a 2005 horror film , directed by Bruce Hunt. It stars Cole Hauser , Eddie Cibrian , Morris Chestnut , Marcel Iureş , Lena Headey , Rick Ravanello , Piper Perabo and Daniel Dae Kim .
The film begins deep in the Carpathian mountains of Romania during the Cold War, where a group of Russian explorers are searching for an abandoned 13th century abbey . As they venture inside and below the church, they make a startling discovery: the abbey is built over the entrance to a giant subterranean cave system. When they try to blast their way in, they cause a landslide that buries the abbey and the men are trapped in the cave below it. Then they hear strange pinging sounds coming from the darkness. They are never seen again.
30 years later, a team of archeologists are conducting an excavation of the ruins of the same abbey and discover the cave system. These scientists are Dr. Nicolai and his associate Katheryn Jannings. Local biologists believe the cave could contain an undiscovered ecosystem , so they hire a group of American spelunkers lead by Jack McAllister and his brother Tyler to help them investigate its unknown depths. Jack and Tyler are thrill-seeking professional cave explorers who run a world famous team of divers . They arrive in Romania with the latest equipment, including a modified rebreather system allowing a diver to remain submerged for up to 24 hours. The diving team includes rock-climbing professional Charlie, first scout Briggs, sonar expert Strode, survival expert Top Buchanan, and cameraman Alex Kim.
As they begin the expedition, they send Briggs to find the first advance base camp, much to Tyler's displeasure as he is the best scout, but Jack thinks otherwise. When they lose contact with Briggs, they all dive in to find him. When Strode wanders off, he is suddenly attacked by an unknown creature. When he is dragged away, his water scooter explodes and causes a cave-in. Jack resolves that they must find another way out, Katheryn and Nicolai begin examining the bizarre biology in this cave, which they discover a strange parasite in all of the lifeforms they find. When Jack gets stuck in a shaft, he is suddenly attacked by the same kind of creature that killed Strode, but Jack manages to break free from its claws; still, he is slightly injured.
All known cave creatures today are variations of outer-world creatures that have simply adapted for cave life over generations, but Katheryn believes this new parasite to be life that originated in the cave environment and never been exposed to the outside world.
As the team heads deeper into the cave, they occasionally stumble across scattered equipment and remains of the previous explorers, and are unaware they are being stalked by the creatures. The team begins to question Jack's leadership as he leads them into unknown passages without second thought, and becomes more unstable since he was attacked, but Tyler assures the team to trust him. Jack also begins to exhibit a transformation of his senses, and physical features. When he leads them to rapids that flow to an underground lake, the creatures attack again, Katheryn is unharmed but Dr. Nicolai is dragged away; but as Jack tries in vain to free him, he sees the creatures are demon-like humanoids, and notices a recognizable tattoo on one of them. The team then reaches a vast delta in the underground river with large walls. As the team and Jack argue about where to go next, Charlie climbs the wall to an opening for a possible exit. But when she reaches the opening, she is jumped by one of the creatures, she manages to kill it with improvised weapons but she is gutted by the creature and dies, when Jack tries to save her, he has another transformation that slowed him down. As the team mourn over Charlie's death, they see Jack's transformations are beginning to show. Katheryn then concludes that his transformations are from the parasite they discovered, for it has entered his body through his wounds from his attack and is affecting his nervous system. Remembering the remains of the previous explorers and the tattooed creature, we realize that the creatures are the previous explorers. They were transformed as the result of the symbiotic parasite that infects its human host and begins to mutate it into these mutant- humanoid demons, built for surviving in cave environment. They have wings, amphibian skin, echolocation hearing (which are the strange sounds of them navigating), sharp teeth, and long claws. They are no longer human and now they hunt down and slaughter anything and anyone that enters their new home. They realize Jack is quickly evolving into one of them, the team splits up, shattering their trust in Jack, but Tyler and Top stay with him.
Jack leads Tyler and Top down an ice cave, Top falls and breaks his leg but they manage to find a way through the ice; and they find a hellish cavern littered with skeletons. They realize this is an ancient battleground between the creatures and the Knights Templar where the knights clearly lost, the ones who built the church at the entrance to seal the cave to prevent future generations from entering and keeping the demons from getting out of the cave environment. When Jack finds the cave's exit, he has another transformation, at this point he is now barely human and in no condition to find the rest of the team. As Tyler heads back to find the others, the creatures enter the cavern and steal their diving equipment necessary to get through the exit. Tyler finds Briggs hanging from the ceiling of a section of the cavern, suspended by stalactites and barely alive, Briggs points his pupils in the direction the creature went; Katheryn manages to save Tyler from being attacked when she uses their sonar gun to distort the creatures hearing. Tyler and Katheryn swim to the ice cave, she nearly drowns but Tyler does CPR to save her. They regroup with Alex and they make it back to the exit. Jack tries to steal back their rebreather while the rest of the group fight off the creatures, but Alex is killed and eaten. When they are surrounded, Jack causes an explosion with the rebreather and causes the cave to collapse; he stays behind to fight the creatures off, presumably killed by the cave-in. Tyler, Kathryn, and Top escape the cave and are back on the surface.
They return to civilization and part ways. Tyler asks Katheryn if Jack could've survived out in the open, she is silent, then says that the parasite that was changing him made her think that it could only survive underground, but is now uncertain. When she kisses him, she moves her sunglasses down below her eyes, revealing pupils similar to Jack's when he first showed signs of infection, Tyler suddenly discovers that Katheryn is infected with the parasite, and supposedly has the intent to "infect the rest of the world." He runs after her into a crowd of people, but she has disappeared.