Logline

An alien living inside a massive cave system stalks the unsuspecting members of a cave tour, forcing the group’s only woman to fight back in order to protect the survivors.

Lisa and her fiancee John take a weekend trip to a quaint little town for some fun and relaxation. They decide to go on a strenuous cave tour, Lisa the only woman in the group. While many of the others don't think she can handle something so physically demanding, Lisa is determined to prove she can keep up with the guys.

After leading her group through a short tunnel, a creature attacks the tour guide Steve as he emerges behind her. Ptery is a large pterodactyl who has been woke from a 65 million year slumber when a broken lantern burned through the ice she was encased in. Ravenous, she attacks the only food source available - humans.

Lost without a guide, the group bickers as they look for a way out. One-by-one, the men perish. When Lisa is snatched by the mighty predator and left inside her nest, John leaves their group to find her. Following a happy reunion, Ptery strikes again. Lisa is the intended target, but John saves her. In the process, he is fatally wounded and says his good-bye before he dies in her arms. Lisa doesn’t want to go on without him, but runs for her life when Ptery comes after her.

The remaining men in her group finds her. Todd has been critical of Lisa, but steps up into a better leadership role. Kyle has lost his older brother and leans on Lisa for support. Matt is just a jerk who only looks out for himself. Mark is Todd’s friend and more reserved.

Mark is the next to die. The remains four attempt to cross a rope and plank bridge. Ptery causes them problems, but they make it across. Meanwhile, park rangers start a search of the cave when Steve’s group is late returning.

Lisa has found a pack belonging to a former victim. It contains a map and supplies. She also finds a bag with two sticks of dynamite inside, lighters, and a gun with two bullets, left by a crazed man who set out to destroy Ptery, but didn’t make it.

The group is forced to climb up a cone’s interior. While distracted, Matt makes the decision to swipe the gun from Todd. He threatens to shoot the others if they try to stop him. He takes off in the direction of lights that came on. Soon, he finds a lit room, but Ptery also finds him. The others listen in the distance to his agonizing screams.

Lisa makes the decision to stay and fight. Todd and Kyle refuse to go without her. They put together a plan to blow up Ptery. Todd and Lisa each carry a stick of dynamite and a lighter. Ptery confronts Todd, and his attempt to blow her up fails. Lisa tries next. She succeeds, but is left paralyzed from a back injury.

In the hospital, Kyle convinces Lisa that she must go on living without John. Neither are aware of Ptery’s eggs starting to hatch.