Good god, is there anything good I can say about this film? Victoria is invited to Paris by her sister who hangs out with a bunch of uber douchebags that like to play pranks on people. The Catacombs under the city are the hip spot for secret raves. They take Victoria to one and tell her the story of a beast who lives in the tunnels and kills those who wander off alone.
Shortly afterwards Victoria wanders off alone as she is uncomfortable with harassment to join in the skinny dipping that everyone is doing. Her sister, who is very abusive, goes after her and is murdered by a beast while trying to show her the way out.
Victoria, who has some sort of nervous condition that requires lots of pill popping, freaks out and finds her way back to the rave. No one pays any attention to her screams for help. Then the police turn up to bust the rave. Oh thank god, maybe they will listen to poor Victoria... who promptly turns and runs off with the ravers in the opposite direction down a tunnel. Even worse, she bangs her head on the roof of the tunnel, knocking herself out and awakening in total darkness. The rest of the movie follows the ever more irritating Victoria as she runs through the tunnels trying to escape from the beast and find her way out.
She runs around. She screams a lot. She doesn't take good care of her flashlight and everything she does is stupid. The only thing that tops her stupidity is the twist ending of the film.