High Tension - Alexandre Aja

Alexia travels with her friend Marie to spend a couple of days with her family in their farm in the country. They arrive late and they are welcomed by Alexia's father. Late in the night, a sadistic and sick killer breaks into the farmhouse, slaughters Alexia's family--including their dog--and kidnaps Alexia. Marie hides from the criminal and tries to help the hysterical and frightened Alexia, chase the maniac, and disclose his identity in the end.